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Help ALO G X or Y Takes the anti log of the x or y axis of all data elements SCALE will give a correctly scaled plot See also HELP on LOG LN ALN AlongLines Stream Set Menu Photon Help The starting positions of the streamlines will be uniformly distributed along a straight line in the projection of the initial plane defined by InitPln in the STREAMLINES menu After pressing this button PHOTON prompts you to supply the number of streamlines Angle of slope specifying the sine of see SNALFA ANGMIN PIL real default 20 0 group 6 This is used when performing a grid orthogonality check with the GRDCHK command The indices of any cell having an angle below ANGMIN will be displayed ANGMIN may be reset by the user The units of ANGMIN are degrees ANGVEL PIL real group 13 ANGVEL is the angular velocity used by GXROTA to calculate the rotational source terms for cylindrical polar and BFC cases see the help on ROTA for further information ANORTH ANORTH is an integer index used in GROUND to access an array containing the free north face area after blockages are deducted at the current z slab ANYZ See PHENC entry F array of EARTH Arc Geometry Menu Photon Help Arc draws an arc by typing in three points in the input window ARC command in PHOTON The ARC command in PHOTON is used to plot circles and circular arcs An arc or circle is defined by 3 points in 3D space the order of which is significant in the case of an arc as it determines the direction in which the arc is drawn An ARC command consists of four command lines the first of these contains the line type the line colour and the circle indicator 0 means draw an arc 1 means draw a circle The remaining three command lines define the cartesian coordinates of 3 points on the arc Here is an example of an ARC command ARC 1 6 1 0 1 0 1 0 1 0 2 0 3 0 4 0 5 0 5 0 5 In this case a full circle will be drawn in line type 1 and colour 6 through the three points specified If an arc were specified rather than a circle then the line would be drawn from point 1 0 1 0 1 0 1 through point 2 0 2 0 3 0 4 to point 3 0 5 0 5 0 5 Arcs see ARC command in PHOTON Argument setting commands see PIL ARITHMetic ARITHMetic the PHOENICS Input Language PIL can in addition to simple assignment statements of the type name value also express arithmetic The operators recognized are and The delimiters recognized are the brackets and The standard trigonometrical functions such as COS and SIN are also recognized Numerous examples of the use of PIL arithmetic are provided in the PHOENICS Input Library See also PHENC entry PIL ARRAY Command group 1 PIL users may declare and access their own arrays The syntax of an array declaration is ARRAY name type d1 d2 d3 where type is INT REAL CHAR or LOG depending on the type of array being declared and d1 d2 and d3 are integer expressions defining the dimensions of the array The maximum number of dimensions of an array is 3 Examples are ARRAY ARR1 REAL 12 5 declares a 12 by 5 real array ARRAY ARR2 INT 100 declares an 100 element integer array ARRAY ARR3 CHAR NX NY NZ declares a character array of dimensions NX by NY by NZ Character array elements are 68 characters long and defaulted to integer arrays have default values of 0 real arrays of 0 0 and logical arrays of F However the name of the character array e g ARR1 above may not exceed 6 characters Array expressions can be used on the right and or left hand sides of expressions with the limitation that on the right hand side array indices can be only simple variables or positive constants Examples are ARR1 3 4 displays the relevant value from ARR1 ARR2 NX 1 DIFCUT 47 4 assigns a value to ARR2 CH1 ARR3 NX NY NZ assigns a value to CH1 from ARR3 It should be noted that CHARACTER array elements must be evaluated between colons in order to yield their values on the right hand side of expressions as in the third example above Attempts to access an array element outside the declared bounds will elicit an error message The maximum number of arrays which can be declared is 100 The amount of space reserved for array elements is determined by the PARAMETERS MXISP MXRSP MXCSP and MXLSP which are declared in routine ARRJB in the file SATLIT FTN These can be reset by the user to increase the amount of array space available The XC YC and ZC arrays see Group 6 can be accessed on the right and left hand sides of expressions eg XC 1 4 5 6 assigns an element of the X Coordinate array YC NX NY NZ prints out a value from the Y Coordinate array XX 1 ZC 1 3 5 assigns a value to XX from an expression involving the ZC array The indices in the corner co ordinate arrays can be constants or simple variables only Thus the following is ILLEGAL ZC 1 NY 1 1 2 Arrays declaring and accessing see ARRAY ASLP ASLP is a PIL logical variable which activates the Algebraic SLip Model q v for multi phase flow See also and encyclopaedia entries on GREX3 and Advanced multi phase flow for further information ASSEMBLY a PHOENICS VR object type An ASSEMBLY object acts as a container for several linked objects See the description in the PHOENICS VR Reference Guide TR326 ASM an abbreviation sometimes used for Algebraic Slip Model AtPoints Stream Set Menu Photon Help The starting positions of the streamlines are picked up with the cursor

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VR object type A BLOCKAGE object defines a volume of material either solid or fluid For solid blockages materials and heat sources can be specified For fluid blockages momentum sources can also be set See the description in the PHOENICS VR Reference Guide TR326 Blockages see POROSITY BLOK BLOK to employ the arbitrarily adjustable block correction feature of the equation solver set STORE BLOK in the Q1 file Values ascribed to BLOK indicate which cells are to be associated with which block Set FIINIT BLOK 1 0 and INIADD F blocks then defined by PATCH INIT commands should be given consecutive integer values The marker BLOK should be used to identify sections of the solution domain where the values of any solved for variable or the coefficients in the finite volume equations are expected to differ greatly from elsewhere in the domain For example in a conjugate heat transfer problem it would be appropriate to identify each solid component as a separate block The block corrections made for a selected variable every ISOLBK iterations cause large scale influences on the values of the variable solved in this way to be more rapidly transmitted to all parts of the domain by grouping the cells in each block together as if to form a coarser grid In this way the speed of convergence may be improved for certain types of problem particularly those in which different areas of the domain may have widely differing material properties Use of this feature requires IVARBK to be set equal to the index of the variable which is to be solved by the block correction method or to 1 when it is to be used for all variables The nature of the block correction feature is this If the number of blocks created is NBLOK it solves NBLOK simultaneous linear algebraic equations by a direct matrix inversion method The NBLOK unknowns in these equations are the values of the corrections which if applied uniformly to all cells in the individual block of cells would make the nett residuals for the blocks zero The coefficients in the NBLOK equations are derived from the equations for the individual cells by summation in which process the cell to cell links within the block cancel each other out Calls to the block correction feature and to the standard cell wise solver are interspersed within the main iteration loop The corrections are applied as soon as they have been calculated and the individual residuals of the cells within them are then re calculated See also the entry on ISOLBK The block correction feature is illustrated in library cases 100 and 459 to 467 BOOLEAN Command defaults F group 1 BOOLEAN command to declare up to 50 PIL logical variables For example BOOLEAN LOG1 LOG2 LOG3 LOG4 makes LOG1 LOG2 LOG3 and LOG4 recognised as local working logical variables Any name of not more than 6 characters can be used eg BOOLEAN LOGVAR Variables are assigned by the statement LOG1 logical expression

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further information CHAR command see GROUP 1 Chen Kim KE EP Turbulence model See PHENC entry The Chen Kim modified KE EP turbulence Model CHKLEN Advanced PIL command The syntax is CHKLEN VARIABLE LEN FUNC where VARIABLE is any valid PIL character variable or element of a character array LEN is any valid PIL integer and FUNC is any valid PIL logical variable If FUNC is F on entry the length of variable is checked against LEN If it is greater than LEN LEN is reset to the actual length and FUNC is reset to T If FUNC is T on entry variable is truncated to LEN CHKVAR Advanced PIL command The syntax is CHKVAR VARIABLE TYPE LOG The command checks whether VARIABLE is a valid PIL REAL INTEGER LOGICAL or CHARACTER variable as specified by TYPE TYPE may also be ANY to check if VARIABLE exists at all LOG which can be any valid PIL logical variable is set T if the condition is satisfied and F if it is not For the types REAL and INTEGER VARIABLE may also be a number or an expression enclosed in colons LOG will be set T if the number or expression can be evaluated correctly according to TYPE CHSOA Real group 13 CHSOA is a constant used by gxchemso in the calculation of the chemical source terms CHSOB Real group 13 CHSOB is a constant used by gxchemso in the calculation of the chemical source terms CHSOC Real group 13 CHSOC is a constant used by gxchemso in the calculation of the chemical source terms CHSOD Real group 13 CHSOD is a constant used by gxchemso in the calculation of the chemical source terms CHSOE Real group 13 CHSOE is a constant used by gxchemso in the calculation of the chemical source terms CINH1A Real default 0 0 group 10 s CINH1A parameter used in formulae for phase 1 to interface transfer coefficient formulae Further parameters of the same kind are CINH1B and CINH1C See CINT CINH2A Real default 0 0 group 10 s CINH2A parameter used in formulae for phase 2 to interface transfer coefficient formulae Further parameters of the same kind are CINH2B and CINH2C See CINT Circle Geometry Menu Photon Help Circle draws a closed circle by typing in three points in the input window CLIPPING PLANE a PHOENICS VR object type A CLIPPING PLANE object is used to graphically clip the screen image It has no effect on the solution See the description in the PHOENICS VR Reference Guide TR326 CLR CLR is a PIL command which may be issued during an interactive session or inserted in a Q1 file Its effect is to clear the screen Library case 374 illustrates its use for introducing a new display sequence after another library case has just been loaded CMDOT is a PIL variable Real default 0 0 group 10 CMDOT interphase mass transfer parameter for ONEPHS F The mass transfer rate positive from phase 2 to phase 1 is equal to CMDOT FIP where FIP is the reference inter phase transfer coefficient determined by the setting of CFIPS If CMDOT equals GRND EARTH visits SECTION 2 of GROUP 10 of GROUND HTM for a user supplied value of the interphase mass transfer rate for each cell at the current IZ slab This EARTH array of values is addressed in GROUND by means of the integer flag INTMDT If CMDOT is set equal to GRND1 GRND2 GRND9 built in coding is used instead This is to be found in the open source file GXIMAS HTM where the options are CMDOT GRND1 selects the mass transfer rate equal to CMDTA FIP R2 CMDTB CMDOT GRND2 selects the mass transfer rate equal to CMDTA FIP R2 CMDTB CMDTC CMDOT GRND3 selects the mass transfer rate equal to A R2 B C MixF This option is useful when the mass transfer rate is limited by the saturation of the first phase C being the saturation value of the mixture fraction MIXF CMDOT GRND4 selects the mass transfer rate equal to CMDTA R1 CMDTBB R1 R2 CMDTC CMDOT GRND5 makes the mass transfer rate linearly dependent on abs dU dX CMDOT GRND6 selects the mass transfer rate linearly dependent on sqrt abs dP dX 1 Rho1 1 Rho2 CMDOT GRND7 8 9 make no selection at present If CMDOT is set to HEATBL however the rate of interphase mass transfer is computed from the balance of heat transfer to the interface from both phases according to the following expression COI1 H1 PHINT H1 COI2 H2 PHINT H2 S PHINT H1 PHINT H2 In this expression the denominator is the latent heat of vaporization COI1 is the transfer coefficient for enthalpy from the bulk of phase 1 to its interface with phase 2 COI2 is the transfer coefficient from the bulk of phase 2 to its interface with phase 1 and S denotes the sensible heat transfer from bulk to interface supplied by the material approaching the interface This is equal to the mass transfer rate H2 PHINT H2 for CMDOT 0 0 and the mass transfer rate H1 PHINT H1 for CMDOT 0 0 CMDOT HEATBL is often used for steam and water systems where evaporation and condensation occur at the steam water interface CMDTA Real default 0 0 group 10 s CMDTA parameter used in interphase mass transfer formulae Further parameters of the same kind are CMDTB CMDTC CMDTD CMDOT CMPRS1 is an integer equal to 2 which is used to indicate that the first phase compressibility d ln rho1 dp is to be selected in GROUND subroutines such as gxprutil htm CMPRS2 is an integer equal to 4 which is used to indicate that the second phase compressibility d ln rho2 dp is to be selected in GROUND subroutines such as gxprutil htm CO CO is an integer index used in GROUND It refers to the storage location of the coefficient array and is used to set the coefficients of linearised source expressions COEFFicients The third argument of the COVAL command is known as the COefficient It is in essence the constant of proportionality connecting the source to be set by COVAL with the excess of the nodal value of the variable in question indicated by the second argument of COVAL over the fourth argument of COVAL known as the VALue Any numerical magnitude can be entered for a COefficient but some have special significances These are provided with names which are recognised in PIL Their names and magnitudes in brackets are FIXFLU 2 E 10 FIXVAL 2 E10 FIXP 1 0 OPPVAL 10250 0 ONLYMS 0 0 ZERO 0 0 GRND 10110 0 GRND1 10120 0 GRND2 10130 0 GRND3 10140 0 GRND4 10150 0 GRND5 10160 0 GRND6 10170 0 GRND7 10180 0 GRND8 10190 0 GRND9 10200 0 GRND10 10210 0 See COVAL for further information COI1 COI1 is an integer index used in GROUND It refers to the storage location of the inter phase transfer coefficient from phase 1 to the interface COI2 COI2 is an integer index used in GROUND It refers to the storage location of the inter phase transfer coefficient from phase 2 to the interface The COLDAT file This file resides in phoenics d allpro and may be seen by clicking here It contains data specifying the colours to be used in PHOTON and SATELLITE menus Users who wish to use other colours than those in the above file should replace the line COLDAT phoenics d allpro coldat in their private PREFIX file by a similar line which indicates where the desired coldat is to be found Convection fluxes for cartesian co located velocities balances in BFCs In present implementation of non staggered algorithm U1 V1 and W1 will still be solved for but the values of these quantities will be over written just after they have been solved by PHOENICS with values which have been obtained from the cell face velocity interpolation formulae At this point these are the convection fluxes for cartesian co located velocities balances in BFCs that deserve special attention Two practices are employed to calculate the mass fluxes from cell face values of cartesian velocities on general non orthogonal curvilinear grids The first is used when NONORT T and second is at present recommended for general use followed by NONORT F which is default value The distinction between them will now be discussed in brief When NONORT T the cell face cartesian velocities are transformed to velocity resolutes aligned with local direction of the grid and replace U1 V1 and W1 to provide the mass flux calculations by EARTH procedure taking into account the contributions from non in face resolutes In contrast if NONORT is set F U1 V1 and W1 are over written by values of mass fluxes directly calculated from cell face cartesian velocities and surface areas of the cell faces Then the area projections used by EARTH in the formulae for mass fluxes are removed The advantage of this practice is the exact mass flux calculations for the grids with significant departures from orthogonality without any need for special treatments like NONORT T option The four new low dispersion convective schemes with local oscillation damping facilities have been implemented by introducing the additional source terms to provide for the differences between the desired formulation and the UDS one So the whole set of the convective schemes available for non staggered calculations now includes seven formulations COMBUSTION Relevant links Combustion related items in the Applications Album Lectures and Tutorials Simple Chemically Reacting System SCRS Extended Simple Chemically Reacting System ESCRS CHEMKIN Combustion Tutorials Combustion 2008 More recent lectures or publications Turbulent mixing and chemical reaction the multi fluid approach The simulation of smoke generation in a three dimensional combustor Connexions between the Multi Fluid and Flamelet models of turbulent combustion CFD Applied to combustion past present and future MFM applied to a turbulent diffusion flame Turbulent combustion models for CFD in the year 2000 The Fortran sub routine gxchemso htm for chemical sources About the EXPLOITS special purpose program COMBUStion processes can be represented by PHOENICS if suitable settings are made of thermodynamic and transport properties see PROPERTIES and reaction rate sources see REACTION RATE Radiative effects can also be modelled if required see RADIATION for details GREX contains the simple chemical reaction scheme SCRS model in which fuel and oxidant are presumed to combine in a single step to form a product viz FUEL OXIDant PRODuct Two options are provided namely the mixing controlled reaction rate option and the kinetically controlled reaction rate option The PIL settings common to both options are NAME 16 MIXF SOLVE MIXF STORE OXID PROD CHSOA MIXture Fraction mass fraction of fuel whether burned or not at which stoichiometric conditions prevail TMP2B the heat of reaction of the fuel CP1 GRND10 CP1A the specific heat of the fuel CP1B the specific heat of the product CP1C the specific heat of the oxidant RHO1 GRND6 RHO1A the molecular weight of the fuel RHO1B the molecular weight of the oxidant RHO1C the molecular weight of the product The two options are distinguished from one another by the following settings for option a STORE FUEL TMP1 GRND7 for option b SOLVE FUEL TMP1 GRND8 and in addition one of the reaction rate sources see REACT must be selected Library case 492 exemplifies the use of the SCRS model COMMANDER See PHOENICS Commander Component Vector Edit Menu Photon Help Component specifies the three components of the vectors can be used to set a particular component to zero Composite flux model activating the see RADIATion command Group 7 Compressibility of phase 1 fluid see DRH1DP real Group 9 Compressibility of phase 2 fluid see DRH2DP real Group 9 Compressible gas flows convergence in Convergence is sometimes difficult to achieve for high Mach number flows when as has often been the practice in the past the temperature has been deduced by subtracting the kinetic energy of the time mean motion from the stagnation enthalpy The recommended practice is to interpret H1 as the specific enthalpy of phase 1 not its stagnation enthalpy and to activate or rather not deactivate the built in source terms for this variable which represent the work done by the mean pressure as a consequence of its variations with time ie kp kt the work done by the mean pressure gradient in space as a consequence of the velocity field ie uikp kxi summation convention used and the viscous dissipation effected by the interaction of the effective viscosity of the fluid with the shearing motion ie tijkui kxj where t denotes the shear stress summation convention used Computations which proceed in this way converge much more smoothly than those proceeding by way of stagnation enthalpy and in most cases they lead to identical results In just one respect however they may be deficient when strong shocks appear in the flow the built in calculation of the viscous dissipation term may be an underestimate because it cannot calculate correctly the velocity gradients in the shocks In these circumstances ad hoc additions may be needed the magnitudes of which can be calculated from well known thermodynamic relations COMPRESSED PHI files are created when in the cham ini file the following line appears compress on PHI file so compressed are usually less than half the size of the uncompressed file The compression is handled within EARTH and both PHOTON and the VR Viewer can read such files There also exist stand alone compression and de compression utilities which can be applied to individual files Computational domain The portion of physical space in which the problem is solved CON1E CON1N CON1H CON2E CON2N CON2H CON1E CON1N CON1H CON2E CON2N CON2H are the block location indices of the convection fluxes i e the mass flow rates across the east north and high cell faces for the first and second phases respectively They are stored in blocks of length NX NY NZ in the F array Therefore the value of CON for the cell characterised by the indices IX IY and IZ can be accessed as F L0f con IY NY IX 1 NX NY IZ 1 CONFIGuration files CONFIGuration files are those which are read by the various PHOENICS executable modules for information on the locations and natures of the files which must be accessed during execution There is a CONFIGuration file for each PHOENICS program residing in the relevant directory as follows SATCON in d satell MENCON in d satell EARCON in d earth PHOCON in d photon AUTCON in d photon PINCON in d utils In addition a file called CONFIG which is common to all programs resides in d allpro Users are advised not to modify these files in any way Confirm C Photon Help Confirm the range of DELETE OFF or ON Conjugate Gradient Solvers in PHOENICS Three versions of conjugate gradient solver are available as follows name CSG3 value Notes conjugate gradient CNGR recommended conjugate residual classical pre conditioned CGGR Suitable for solving for pressure and velocities congugate residual explicit residual CRGR Suitable for any variable The first can be activated for all variables by setting CSG3 CNGR in the Q1 file or it can be activated for individual variables by the appropriate setting of ENDIT To call either of the last two solvers the user should set USOLVE T and choose the name of the solver by appropriate setting of CSG3 variable in Q1 file Relevant Fortran coding is to be found in the open source file GREX3 HTM The Fortran of the three solvers themselves is in the closed part of EARTH See also PHENC entry icngra b c CONPROM a means of activating CONWIZ the convergence wizard can be activated by loading into the q1 file a PIL macro called conprom an abbreviation of convergence promoter This is done by inserting the line conprom into the Q1 file how this works is explained here CONTACT resistances The Group 12 feature allowing diffusion coefficients to be modified patchwise has been extended to allow the addition of resistances to heat transfer brought about by the inclusion of thin sub grid scale sheets of poorly conducting material For more information see the Encyclopaedia entry PATCH Continuity imbalances of phase 1 see IMB1 integer name Group 7 Continuity imbalances of phase 2 see IMB2 integer name Group 7 CONTUR Real flag value 25 0 group 23 CONTUR is a PATCH type specification which indicates that one or more contours are to be plotted at field print out time for the PATCH in question The numbers of columns and rows to be occupied by the contour plot are dictated by the values given to the variable NCOLCO and NROWCO respectively their default values are 45 and 20 ICHR controls whether odd even or both value bands are filled with characters See PATCH and TYPE for further information CONTUR plots setting columns for see NCOLCO Convection and diffusion adjustments see GROUP 12 Convection fluxes accessing and altering see UCONV Convection neighbours accessing or altering see UCONNE Convection schemes see Schemes for Convection discretization CONWIZ a PIL variable of boolean type default F which activates the PHOENICS convergence wizard It is currently effective only for structured grid PHOENICS Copy grid meshes see GSET C command Group 6 COPYQ1 file All syntactically valid data setting commands and comments ie command categories 1 2 and 6 read from the Q1 file or supplied during the interactive session are written to the file COPYQ1 Thus if the computer system crashes during a TALK session the entries already made are not lost CORIOL Real default 0 0 group 13 CORIOL when set to a value other than zero causes momentum sources per unit mass which are equal to CORIOL V1 for U1 CORIOL U1 for V1 and to corresponding expressions for the second phase velocities This facility is useful for representing Coriolis forces in horizontal flows for example atmospheric or

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logical default F group 8 EQDVDP when T sets the d vel dp s of the first and second phases equal to the weighted average of the two eg thus d U1 dp d U2 dp r1 d U1 dp r2 d U2 dp EQUAL Autoplot Help EQ UAL Enters equal mode in which plots are drawn so that both axes are scaled equally This is the default for BFC grid file plots See also HELP on UNEQUAL EQUAL command in AUTOPLOT There may be occasions when it is desirable to have distances along the axes equal in the two coordinate directions This is achieved by using the command EQUAL When EQUAL is used either the full x width or the full y height will be used but usually not both To revert to the ordinary mode of operation you should use the inverse command UNEQUAL EQUAL is the default when plotting BFC grids Note that when EQUAL is used the SCALE X and SCALE Y commands require an additional piece of information since rescaling in for instance the x direction will affect the y scaling also After one of these commands the following question will appear CONSTANT VALUE OF Y or X You should respond with the value of y or x which is to remain at the same position on the screen after rescaling Use of the MAGNIFY command instead of SCALE X or Y avoids this problem When one of the axes is logarithmic exact equality of axis distances may not be achieved since the scales will always be forced to lie within the nearest powers of ten If the plot size is changed while in equal mode by typing BIG FULL LITTLE or PAGE a further SCALE command will be necessary to re enforce equality of the axis markings Equations solved by PHOENICS See PHENC items Differential equations Auxiliary equations Finite volume equations EQUVEL EQUVEL is PIL logical variable which it is useful to set T when two distinct phases are present having different temperatures and or compositions so that it is necessary to set ONEPHS F but the interphase friction is great enough perhaps because of the fine subdivision of a particulate phase for the difference of velocity between the two phases to be negligible It can be regarded as an economising device for it allows one set of velocities to be computed rather than two Input file library cases employing this device include 483 484 485 w100 w468 w574 w576 An IPSA based two phase flow Q1 can be converted to one based on the equal velocity assumption simply by adding to the bottom of the Q1 file the line LOAD W100 or to make what is being done even plainer L EQUALVEL Here EQUALVEL is a non PIL character string which is declared in the always loaded first macro 014 where it is given the value w100 which of course has the desired effect Reminder the prevents the loading of a new case

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reduce the size of a PHI or PHIDA file by removing from it those fields which they do not need It is activated by way of the runfil or runfils command FINE GRID EMBEDDING See also entry PARSOL Accuracy of simulation often requires that the computational grid should be very fine around regions of the domain exhibiting steep gradients of temperature concentration density or other significant fluid property In earlier versions of PHOENICS this entailed also extending the fineness into regions where it was not required Fine grid embedding now available renders this unnecessary for it is possible to refine the grid ONLY where necessary Click here to see an application to a three part airfoil See the PHENC entry multi block grids and fine grid FIRE a FLAIR object specifying a heat mass and scalar source See the description in the FLAIR User Guide First sweep index number of see FSWEEP First phase cartesian velocity resolute see UCRT VCRT WCRT character First phase fluid mixing length scale of see EL1 First phase temperature integer index for see TEM1 FIXCOR PIL real default 1 E10 group 6 FIXCOR parameter used to anchor coordinate points in sub domains specified by FIXDOM when the MAGIC L option is used When FIXCOR is set to a value less than 1 E10 the effect is to introduce a resistance to movement of the coordinates within the sub domain specified by FIXDOM The smaller the value of FIXCOR the less the resistance is This device can be used to reduce the movements of the coordinates which the Laplace solver brings about See FIXDOM MAGIC for related information FIXDOM Command group 6 FIXDOM command used to specify up to 10 sub domains in which it is desired to keep the coordinate points fixed when the Laplace corner coordinate solver MAGIC L is invoked It has seven arguments the first specifies the sub domain number from 1 to 10 the remaining six arguments locate by their index numbers the sub domain boundaries of the corner coordinates that are to be kept fixed ie FIXDOM sub domain no first I last I first J last J first K last K When the DOMAIN over which MAGIC L operates includes a solid the FIXDOM command may be used to prevent the Laplace solver from moving the corner coordinates that correspond to the locations of the solid It is also useful where one wishes to retain a fine grid zone which otherwise MAGIC L might coarsen See MAGIC FIXCOR for related information Fixed pressure boundary see OUTLET Fixed flux boundary condition see FIXFLU Fixed value boundary condition see FIXVAL and FIXP FIXFLU PIL real flag value 2 0E 10 group FIXFLU is a coefficient name recognized in the third argument of COVAL to be used to indicate a fixed flux condition See COVAL for further information FIXP PIL real flag value 1 0 group 13 FIXP is a coefficient name recognized in the third argument of COVAL to be used

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draw the projection of a PATCH on a specified grid plane Format GPROJ Patch name dir ipl icol idash arguments dir X Y or Z ipl the number of the X Y or Z plane on which the projection is made icol the colour index itype the line type index 0 for solid line 1 and upwards for dashed lines Note that the patch name is not displayed with the projection GRDCHK Command group 6 The syntax is GRDCHK PLANE LOC1 LOC2 NOPLOT This command performs a BFC grid orthogonality check on an I J or K plane as specified by PLANE LOC1 is the number of the first plane to be checked and LOC2 is an optional parameter showing the last plane to be checked Thus GRDCHK I 1 checks I plane 1 and GRDCHK K 3 NZ 1 checks K planes 3 through to NZ 1 For each plane specified the minimum angle in each cell is calculated and displayed by colouring the cells in the range from blue to red where red denotes 90 degrees and blue 0 degrees The optional last parameter NOPLOT disables the graphical display The angle calculated is 90 minus the angle between a line joining adjacent cell centres and the normal to the cell face separating them This is done for each of the four faces on the plane and the smallest angle is chosen Fully orthogonal cells will have angles of 90 degrees If any cells have angles below ANGMIN their indices are displayed See ANGMIN for details GREAT Real flag value 1 0E20 GREAT A large number used in EARTH Do not re set The default value may be re set during installation to suit the precision of the computer GRSP1 GRSP1 is an integer index usable in subroutines called from GROUND for accessing the 2D array of values pertaining to the current IZ slab of values of anything the user determines In order to provide storage for the array indexed by GRSP1 subroutine MAKE must be called from Group 1 section 1 of GROUND Similar indices are GRSP2 GRSP3 GRSP10 These indices are reserved for use in GROUND and are guaranteed not to be used in any way in GREX or the GX suite GT NAME When the character is the first character of a patch name and the second third fourth and fifth characters are the name of a stored or solved variable a source is created which is equal to CO VAL S PHI where S is the local value of the above mentioned stored variable and PHI is the local value of the variable to which the source is applied For example the following statements in a Q1 file PATCH W1 CELL NY 4 1 NY 2 NZ 4 1 NZ 2 1 LSTEP COVAL W1 V1 1 0E3 1 0 will provide a source of V1 which equals 1 0E3 W1 V1 This will tend to make V1 equal to W1 GTEXT PIL Graphics command

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HEATBL PIL real flag value 10240 0 grou HEATBL is the flag to which CMDOT should be set in GROUP 10 if the mass transfer rate from one phase to the other phase is to be computed from a heat balance HEATBL has a pre set value 10240 0 which should not be changed See also CMDOT and PHINT Height of liquid method H O L HEIGHT OF LIQUID METHOD Flow simulations of real processes often involve fluids that are separated by a sharp interface Mould filling film coating wave formation liquid sloshing in tanks are some examples The calculation of the interface is usually a computer intensive task and yet a necessary step in the solution procedure and often the main output from the computation PHOENICS offers several ways of tracking such an interface such as DONACC in two phase mode or the scalar equation method see PHENC entry SEM An addition to PHOENICS allows the economical tracking of the interface when it is known beforehand that the surface does not exhibit overturning The method called Height Of Liquid HOL calculates the height of the interface at each point by focussing on one of the fluids say the lower one and computing the height of the liquid column through a mass balance over the sides of the column HOL works computationally as a single phase method and it can be used in all three coordinate systems and for transient and steady state problems HOL is attached to PHOENICS as a GROUND station and delivered in source code It forms a part of the advanced multi phase option The activation of the HOL features is from PIL or from PHOENICS VR Details of how to activate HOL are provided in the HOL method lecture which appears in the multi phase section of the general lectures on PHOENICS HGSOA PIL real group 13 HGSOA is a constant used by GXLATG in the calculation of horizontal gravitational forces resulting from differences in a liquid layer depth in a pipe The constant is used as an iteration convergence criterion See the help on GRAV for further information HGSOB PIL real group 13 HGSOB is used to specify the difference in densities between the first and second phase fluids in a two phase pipe flow case for which a lateral gravitational acceleration of the fluid is required See the help and encyclopaedia entries on GRAV and GXLATG for further information HIGH PIL real flag value 6 0 group 13 HIGH is a PATCH type used for setting sources per unit high ie larger z area by way of COVAL in group 13 HIGHER ORDER SCHEMES See PHENC entry SCHEMES for convection discretization HIGHLO PIL logical Switch HIGHLO when set to true activates checks to ensure that corrections to the dependent variables lie within the limits defined using the variables VARMIN and VARMAX HOCS acronym for higher order convection schemes See PHENC entry SCHEMES for convection discretization HOL PIL logical default F group 19 Set

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Open archived version from archive - ENC_I.HTM

F are those which prevail at the current time step the implicit formulation is said to be in use This is what is used when N is entered as the 6th argument of SOLUTN it is the default and it is recommended for general use When Y is entered as the 6th argument the neighbour values are taken as those which prevailed at the end of the previous time step the explicit formulation is said to be in use This option may be used to effect computer time economies when the so called Courant criterion is satisfied namely u dt dx 1 where dt and dx refer to the time and space step sizes and u is the velocity One may wish to select for explicit treatment those variables which change much more slowly with time than other variables again for reasons of economy See PHENC entry schemes INCHCK PIL integer default 1 group 25 INCHCK element number of F array the value of which is checked to be greater than SMCHCK and less than BGCHCK The number may be obtained by setting DBINDX T INCL a PIL command Insertion of INCL file name on a single line in a Q1 file with or without a closing bracket will load the named file into the instruction stack with the same effect as though the contents of the file resided in the Input File Library If lines containing TALK or STOP are present in the file these lines will be ignored Q1 s can therefore be swallowed whole This feature enables users to use the same set of instructions in many different Q1 files without having to copy them in The so loaded file can itself contain l or incl commands Independent time flows setting of see STEADY Independent variables In general a phenomenon simulated by PHOENICS will be four dimensional the four dimensions being time and three space dimensions The latter are called for ease of reference north south east west and high low Specifically t measures time in the early to late direction x measures distance or angle in the west to east direction y measures distance in the south to north direction and z measures distance in the low to high direction INDVAR Ground integer INDVAR is the number of current dependent or auxiliary variable number INFLO PIL real flag value 23 0 group 13 INFLO is a PATCH type used to specify PATCHes at which only inflow is desired Thus where a pressure boundary condition prevails at such a PATCH cell pressures in excess of the outside pressure do not cause outflow INIADD PIL logical default F group 11 INIADD controls whether or not the initial fields which are set by way of FIINIT PATCH and INIT are additive over intersecting PATCHes When INIADD is T they are added When INIADD is F they are not added and the last PATCH overwrites what is implied by FIINIT and any preceding PATCHes The CONPOR command unconditionally resets INIADD to F It is also set to FALSE in EARTH whenever PRPS is stored and its value is set to a value which is present in the PROPS file for the addition of such values can have no physical significance INIFLD PIL logical default F group 21 INIFLD may be set to T if it is desired that the initial fields should be printed See FIINIT to learn how these are set IniPln Stream Menu Photon Help IniPln specifies the initial seeding plane All streamlines will be drawn from this plane See also Set INIPOL a reserved patch name When the grid is cylindrical polar and it is desired to create an initial velocity field which is uniform the following provisions in the Q1 file will have the desired effect INIADD F PATCH INIPOLxx INIVAL 1 NX 1 NY 1 NZ 1 1 INIT INIPOLxx U1 0 0 GRND INIT INIPOLxx V1 0 0 GRND FIINIT V1 absolute velocity in the XY plane FIINIT U1 angle in radians between the direction of the velocity and the angular x axis INIT Command group 11 INIT is a command used for setting PATCH wise initial conditions It has four arguments Initial values may be inserted PATCH wise by means of the commands PATCH and INIT In the former INIVAL must be inserted as the second entry thus PATCH patch name INIVAL first IX last IX etc Then the INIT command follows for all variables which it is desired to set in this way as INIT patch name variable name or index ZERO value See the Encyclopaedia entry INITIAL CONDITIONS INIVAL PIL real flag value 26 0 group 11 INIVAL is a PATCH type used in group 11 for specifying zones of constant initial values specified for a given field variable by the 4th argument of INIT See INIT for further information INLET a PHOENICS VR object type An INLET object defines an area of fixed mass flow The mass flow can be specified as density and velocity or density and volumetric flow rate or massflow The direction of the massflow inflow or outflow is set by the sign of the velocity or flow rate See the description in the PHOENICS VR Reference Guide TR326 INLET Command group 13 This command is used to declare inlets i e fixed mass inflow boundaries Used in conjunction with VALUE it does no more than can be done via PATCH and COVAL but is slightly more compact and conceptually easier to deal with As well as the mass flow rate per unit area non zero values of velocity and scalar quantities convected in by the mass flow can be specified by the VALUE command See the entry on VALUE for more information The syntax is INLET NAME TYPE IXF IXL IYF IYL IZF IZL ITF ITL NAME is a unique identifier for the INLET up to 8 characters in length TYPE can be NORTH SOUTH EAST WEST HIGH or LOW and specifies which cell face areas will be used to multiply the mass flow set IXF ITL specify the limits in space and time over which the mass source is to be active Thus REAL WIN RHOIN WIN 3 RHOIN 1 0 INLET INL1 LOW 1 NX 1 NY 1 1 1 LSTEP VALUE INL1 P1 RHOIN WIN VALUE INL1 W1 WIN specifies an INLET extending from IX 1 to NX IY 1 to NY at IZ 1 active over all time steps in which mass is entering the LOW faces of the cell at a rate of RHOIN WIN unit area The function of the command is to generate a PATCH with the NAME and TYPE specified over the set limits COVALs are also generated for all solved variables with ONLYMS 0 0 for the COefficient and VALue except for P1 and P2 if NOT ONEPHS which has COefficient FIXFLU VALue 0 0 See the entries on SOURCE PATCH COVAL TYPE and FIXFLU for further details Inlets declaring of see INLET Inner iterations specifying number of see LITXC Inner radius specifying the see RINNER Input sources simplification of see IURVAL Input Window Input Photon Help Input Window is used to type in the coordinates of each point of the geomentry Instruction stack clearing the see CLEAR INTEGRATION The solution of the differential transport equations is sometimes called numerical integration of the equations Integration domain specifying length of see XULAST Integration domain specifying the number of sub divisions in see NX Interface value of variables see PHINT Interpolation see Alternative Interpolation Schemes Intervals Photon Help Intervals shows the number of intervals if the current CONTOUR element was drawn with isolines Intervals setting of see GRDPWR command INTFCO Integer used in GXIFRIC to denote interphase friction coefficient INTMTR Integer used in GXIMAS to denote interphase mass transfer rate INTRC1 Integer used in GXIDIF to denote phase 1 to interface transfer coefficient INTRC2 Integer used in GXIDIF to denote phase 2 to interface transfer coefficient INTVL1 Integer used in GXIVAL to denote interface value for a first phase variable INTVL2 Integer used in GXIVAL to denote interface value for a second phase variable IOPTN IOPTN holds the value of the PHOENICS option which has been installed and which governs the capabilities of PHOENICS which may be activated See also the Encyclopaedia entry OPTIONS The value of IOPTN is locked into EARTH at the time of installation and cannot be changed by the user IPARAB PIL integer default 0 group 14 IPARAB specifies the pressure boundary type for parabolic calculations i e PARAB T IPARAB 0 instructs EARTH to deduce the pressure downstream of each z slab by reference to total mass continuity This option is for use in flows whose lateral i e x wise and y wise boundaries are confined ones as in pipes and ducts generally Other options are IPARAB 1 means that the pressure downstream of each z slab is set by the parameter PBAR This option is for parabolic calculations in which the lateral boundaries are unconfined as in boundary layers jets wakes and etc It is the user s responsibility to specify the downstream pressure by way of PBAR IPARAB 2 This is like IPARAB 1 but in addition it implies that the pressures to be used in the x direction momentum equation are also fixed IPARAB 3 This is like IPARAB 2 but it is the y direction momentum equation which employs fixed pressures not the x direction one IPARAB 4 This option can be used for hyperbolic calculations Unlike the other options when IPARAB 4 the z direction velocity is influenced by the lateral pressure variations rather than just the slab to slab average It should be used only when the z direction velocity everywhere exceeds the local velocity of sound Library case 156 makes use of this option IPARAB 5 This option is useful when a supersonic jet emerges into a subsonic atmosphere as for example at the downstream end of a rocket motor A test is then made at each location as to whether the velocity is super or sub sonic and the formulation of the finite domain equations is correspondingly altered so as to maintain uniformity of pressure across the stream in the subsonic region IPLTF PIL integer default 1 group 23 IPLTF first sweep for plots of spot values and residuals On restart runs this should be set to FSWEEP in order to avoid the allocation of a segment of EARTH storage for the information from 1 to FSWEEP 1 which will not be used IPLTL PIL integer default 1 group 23 IPLTL last sweep for plots of spot values etc The default of 1 ensures that if the user has not set IPLTL EARTH will set it to LSWEEP or to LITHYD if PARABolic IPORIA PIL integer group 11 19 IPORIA is used in the specification of porosities that depend dynamically upon pressure for cells for which IZ is no greater than IPORIA See the help and encyclopaedia entries on POROSI and GREX3 GXHOL GXPORA and GXSURF for further information IPORIB PIL integer group 11 IPORIB is used in the initialisation of porosities to simulate different fixed geometries See the help and encyclopaedia entries on POROSI and GREX3 and GXPORI for further information IPRN PIL integer array Read only Internal storage of information set by OUTPUT command The settings of IPRN are based on prime numbers ISLN PHI divisible by 2 3 5 7 11 13 IPROF PIL integer default 1 group 23 IPROF integer controlling the format of line printer plots elicited by PATCH PROFIL as follows IPROF 0 plots one variable at a time horizontally with the last 2 arguments of PLOT determining the scale IPROF 1 plots all those variables selected by PLOT on the same graph The abscissa quantity is horizontal IPROF 2 prints a table containing values of all the selected variables thinned out in accordance with the values of NXPRIN NYPRIN or NZPRIN as appropriate IPROF 3 prints table and diagram For IPROF greater than 0 the third and fourth PLOT arguments have the following significances When they differ and the fourth exceeds the third they represent respectively the lower and upper limits of the ordinate scale as for IPROF 0 When both are equal to zero the scale limits are taken as the maximum and minimum values of the supplied ordinates When both are equal to negative quantities which are the same as PLOT arguments for other variables at the same PATCH the ordinate scales will be the overall maximum and minimum for all the variables in question The number of columns printed horizontally for option IPROF 0 is set by NCOLPF whereas for IPROF 1 2 and 3 the dimensions of the diagrams plotted are determined by ABSIZ and ORSIZ IPROP Index used in GXPRUTIL and elsewhere to indicate which material property is in question IPRPSA PIL integer group 9 IPRPSA is used to carry the PRPS index of the heavier fluid in free surface problems See the help and encyclopaedia entries on Height of liquid and Scalar equation method GXPRPS GXHOL GXSURF and GREX3 for further information IPRPSB PIL integer group 9 IPRPSB is used to carry the PRPS index of the lighter fluid in free surface problems Height of liquid and Scalar equation method See the help and encyclopaedia entries and GXPRPS GXHOL GXSURF and GREX3 for further information IPSA Method used in PHOENICS to solve the system of algebraic equations for two phase flows IPSA stands for Inter Phase Slip Algorithm IROTAA PIL Integer group 13 IROTAA is a switch used to activate a source term for velocities in cases with rotating coordinate systems See the encyclopaedia entry for ROTATIONAL Momentum Sources IRUN Ground integer IRUN is the current run number ISC an integer set by EARTH together with IGR to dictate which section of GROUND GREX3 etc is to be entered See PHENC GROUND ISGx PIL integer default 0 group 19 ISG1 ISG2 ISG3 etc were originally provided as spare integer variables which could be ascribed values in group 19 of the Q1 file and then transmitted to the solver module EARTH via the eardat file They reside in the file which is included in both SATELLITE and GROUND Fortran namely satgrd The common block ISG which is dimensioned in main htm has 100 elements but as will be seen many of them have other names than ISGx These variables have in the course of time become PIL variables used for particular purposes as can be seen by inspecting the common block ISG of satgrd Thus ISG20 has been replaced by MAXSEC which is used in the time out feature Further ISG21 which has not yet been given a PIL equivalent sets the minimum number of sweeps which must be performed regardless of the values to which the residuals have fallen for versions 3 5 1 and beyond only Additionally for version 3 6 and beyond whatever was set in cham ini isg50 1 enforces endpause isg50 2 turns off endpause isg51 1 enforces figures isg51 2 turns off figures whatever the values of ixmon and izmon isg52 1 enforces plots of maximum and minimum values isg52 2 enforces plots of maximum absolute corrections and residuals isg52 3 enforces plots of spot values and residuals ISKINA PIL integer group 13 ISKINA is used to carry the number of iterations to be taken in the calculation of the dimensionless skin friction factor for turbulent wall functions See the help and encyclopaedia entries on TURBUL and WALL and GXWFUN for further information ISKINB PIL integer group 13 ISKINB is a switch used to activate different formulae for the skin friction factor for turbulent wall functions See the help and encyclopaedia entries on TURBUL and WALL and GXWFUN for further information ISLN PIL integer array Read only Internal storage of information set by SOLUTN command ISO Dir View Menu Photon Help Reset the view direction to 1 1 1 ISOLBK This sets the iteration frequency with which the user defined block corrections are performed The default of 0 means that no block corrections are made See BLOK for further details ISOLX PIL integer default 1 group 8 ISOLX parameter controlling the iteration frequency of x wise block adjustments in the linear equation solver ISOLY and ISOLZ activate similar adjustments in the y and z directions The adjustments are performed for any variable not solved point by point The default setting of 1 means that the adjustments will be performed only on the first iteration of each sweep A setting of 2 would indicate only the first 2 iterations and so on A value of zero means that the adjustment is de activated This may prove advantageous when the domain is multiply connected due to the presence of blockage barriers It is frequently advantageous to set the ISOL parameter for the main flow direction to be 0 as this can speed convergence A value of 1 means block adjustment every iteration 2 means every second iteration and so on If LITER phi is negative the block adjustments applied will be displayed at the screen ISOLY PIL integer default 1 group 8 ISOLY see ISOLX ISOLZ PIL integer default 1 group 8 ISOLZ see ISOLX ISTDB1 PIL integer default 1 group 25 ISTDB1 first time step at which debug printed ISTDB2 PIL integer default 1 group 25 ISTDB2 last time step at which debug printed ISTEP Ground integer ISTEP is the time step number ISTPRF PIL integer default 1 group 23 ISTPRF first time step at which fields are printed ISTPRL PIL integer default 10000 group 23 ISTPRL last time step at which fields are printed ISWC1 PIL integer default 1 group 15 ISWC1 first sweep through field for which solution for variables with indices greater than 13 takes place ie H1 H2 C1 C2 C3 C35 Economy may be effected by setting this greater than 1 so that the velocity field has time to settle before time is

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