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  • since then L L e However if L L e the term is positive leading to increased values of EP and reduced values of L The Yap correction may be selected by using TURMOD KEMODL LOWRE YAP which is equivalent to TURMOD KEMODL LOWRE plus PATCH EYAP PHASEM 1 NX 1 NY 1 NZ 1 LSTEP COVAL EYAP EP FIXFLU GRND5 FIINIT IWDIS 0 1 AMIN1 XULAST YVLAST ZWLAST The Yap correction may also be applied to the high Reynolds number form of the KE EP model by using TURMOD KEMODEL YAP d Other matters The FORTRAN coding sequences for the LB model may be found in Group 1 Sections 1 and 2 and in Group 19 Section 3 of subroutine GREX3 in subroutine GXENUT which resides in the file GXPROP FOR and in subroutines GXKESO GXREYN GXREYT and GXLRDF which reside in the file GXTURB FOR The coding sequences for the Yap correction may be found in Group 13 of subroutine GREX3 and in subroutine GXEYAP The convergence of the turbulence equations can be more problematic than with the standard high Reynolds number form of the KE EP model In cases where convergence proves difficult the user is advised to set KELIN 1 which invokes an implicit increase in the relaxation on KE and EP through a different linearisation of the turbulence model source terms Finally the low Reynolds number extension may be applied to the modified KE EP model of Chen and Kim by selecting TURMOD KECHEN LOWRE which is equivalent to TURMOD KEMODL plus the following PIL commands IENUTA 4 PRT KE 0 75 PRT EP 1 15 STORE WDIS PATCH KECHEN PHASEM 1 NX 1 NY 1 NZ 1 1 COVAL KECHEN EP FIXFLU GRND4 For more details the reader is referred to the Encyclopaedia entry provided under CHEN Kim modified KE EP turbulence model e Activation with conjugate heat transfer The PHOENICS default boundary condition for KE EP C1 C2 etc at the fluid solid interface is finite diffusion flux normal to the wall For consistency with the standard PHOENICS default boundary condition this ought to be zero normal flux In order to achieve the desired boundary conditions at the interface the diffusive links through the wall are set to zero by use of the so called Group 12 Q1 facility Thus for example the PIL commands PATCH GP12DFNT CELL 1 NX NYGL NYGL 1 NZ 1 1 COVAL GP12DFNT KE 0 0 0 0 COVAL GP12DFNT EP 0 0 0 0 COVAL GP12DFNT C1 0 0 0 0 will zero the north face diffusion fluxes for KE EP and C1 at the locations defined by the PATCH limits f Examples A number of Q1 files may be found in the advanced turbulence models library of low Reynolds number turbulence models which demonstrate the use of the model 3 Advice on the use of the model Since the low Reynolds number extension does not employ wall functions and the flow field needs to be meshed

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_enc/turmod/enc_t344.htm (2016-02-15)
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  • article PHOENICS encyclopaedia file TURBULENCE MODELS IN PHOENICS 9 LOW REynolds number turbulence models Contents Introduction List of the available low Re models Advice on use of low Re models

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_enc/turmod/enc_tu9.htm (2016-02-15)
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  • ITERMS NPHI LITER NPHI ISLN NPHI IPRN NPHI NAME NPHI DTFALS NPHI RESREF NPHI PRNDTL NPHI PRT NPHI ENDIT NPHI VARMIN NPHI VARMAX NPHI FIINIT NPHI PHINT NPHI CINT NPHI LG 20 IG 20 RG 100 CG 10 Others variables may be entered via SATEAR COMMON block name position in block value followed by comments if desired as in the following example The position of the item in the block can of course be found by counting However a useful table is included below This feature must be used with caution because some resettings of data may conflict with settings made in the satellite For example whole field solution cannot necesarily be switched ON because necessary storage may not be provided but it may be switched OFF by dividing the relevant ISLN by 5 Example LSWEEP 10 ISOLZ 1 CARTES F LITER 14 100 liter H1 ISLN 14 6 whole field solution for H1 PRNDTL 14 0 01 prndtl H1 NAME 7 aw1 name of W1 LDAT 25 t echo The whole field solver will not be set for H1 due to the as the first non blank character in the line Library case 240 illustrates this feature The locations of the variables stored in COMMON blocks are given below Locations in LDAT are LDAT 1 2 3 4 5 6 7 CARTES USTEER YZPR ONEPHS YANGLE SAVE ZANGLE 8 9 10 11 12 13 14 15 16 XCYCLE XZPR EQDVDP UCONV UDIFF UCONNE UDIFNE USOURC UCORCO 17 18 19 20 21 22 23 24 25 USOLVE UCORR STEADY BFC AUTOPS EQUVEL ADDDIF NOWIPE ECHO 26 27 28 29 30 31 32 33 34 UWATCH NOSORT NOADAP UGEOM NEWENT NEWENL NULLPR BLOCKZ NODEF 35 36 37 38 39 40 41 42 TRACE NOCOMM NOCOPY OLDSOL Q1QUIT DMPSTK LSP40 2 43 44 45 46 47 48 49 50 THINX THINY THINZ STCENP STCORN STCORO SAVGEO RSTGEO 51 52 53 54 55 56 57 58 59 NEWRH1 NEWRH2 LINIT SUBWGR INIADD INIFLD WALPRN GALA DONACC 60 61 62 63 64 65 66 67 68 PARAB DENPCO DEBUG DISTIL PICKUP NONORT HIGHLO EARTH USEGRD 69 70 71 72 73 74 75 76 77 78 USEGRX PILBUG SMPLR VOID DARCY UUP VUP WUP OLDSTO NOGRID 79 80 81 82 83 84 XFIX ZFIZ SETBFC MOVBFC LDATSP 2 Locations in IDAT are IDAT 1 2 3 4 5 6 7 8 9 NX NY NZ LUPR1 LUPR2 LUPR3 ISOLBK LUSDA IPROF 10 11 12 13 14 15 16 17 18 19 NUMCOL MAXBLK LUGRF IVARBK LUOLD LUDEP LUPCO LUDVL IRUNN IOPTN 20 21 22 23 24 25 26 27 28 LITC LITFLX NRUN LITHYD FSTEP LSTEP FSWEEP LSWEEP NPRINT 29 30 31 32 33 34 35 36 37 38 LIBREF NPLERR IXMON IYMON IZMON IINIT NLSG1 NISG1 N RSG1 NCSG1 39 40 41 42 43 44 45 46 47 48 IPARAB NFUSER NXFR1 NYFR1 NZFR1 NTFR1 ENTH1 ENTH2 ISWR1 ISWR2 49 50 51 52 53 54 55 56 57 IXPRF IXPRL IYPRF IYPRL NPRMNT ISTPRL

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_enc/read.htm (2016-02-15)
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  • Macro.htm
    VR Editor d Macros for the VR Viewer Contents The function of a VR Viewer macro How to create a macro Running a macro 1 The function of a VRV macro A typical use of a VRV macro is to record a particular view and magnification and then restore it whenever required for example when replaying the macro commands included in a Q1 file for the graphical display of the results Using a macro in this way will guarantee that a sequence of images from different phi files perhaps generated on separate occasions can all use the identical view and magnification settings A macro file can contain a single image or a sequence of images separated by PAUSE commands Macro command files are ASCII text files and can be edited or created by hand using any convenient text file editor 2 How to create a macro Macro files can be created by using the VR Viewer macro facility or by hand editing using any text editor as follows Press the MACRO button on the Hand set This will bring up the MACRO Functions dialog Select Save as new Yes enter a filename then click OK The current view settings will be written to the selected file The default filename is vrvlog IMAGE MACRO Functions dialog save Partial will save a short form of the macro with only non default settings and changes from frame to frame This form is suitable for inclusion in the Q1 embedded between VRV USE and ENDUSE Full will save all settings for each frame resulting in a longer macro but guaranteeing that the images will be reproduce exactly regardless of starting point Pressing F4 or clicking the F4 icon will overwrite the currently selected Save as new file Press the MACRO button on the Hand set Select Append to old Yes then click OK The current view settings will be added to the end of the selected file Individual views will be separated by a PAUSE command Pressing F5 or clicking the F5 icon will add to the currently selected Append file Individual views will be separated by a PAUSE commands Hand editing a file with any text editor The macro files created by the VR Viewer function can be very lengthy especially if the macro is to be included in a Q1 input file in that case many of commands can be removed by hand editing The following two macro files will produce the same images The Macro saved by the VR Viewer macro function The above macro after hand editing As seen only those commands that change a default or change an existing setting need be placed in the macro file The following are simple rules for hand editing The commands must start in the third column or more Comment lines can be inserted using sign in the front of the lines for example Start of frame each individual frame is separated by the PAUSE command Text messages can be added using the msg command for example msg Pressure contours Each message line is restricted to 68 characters and a total of 3 message lines can be displayed in the text message window The individual commands can be shortened as long as the remaining part is unique For example VECTORS can be shortened as VEC CONTOURS as CON and Variables as VAR etc sign can be used to separate the commands on the same line for example Variable Velocity VEC OFF CON ON If the macro is to be added in a Q1 input file the commands must be placed between the statements VRV USE and ENDUSE as follows VRV USE Start of frame VARIABLE Velocity VEC ON msg Velocity vectors PAUSE ENDUSE Once you are getting familiar with the commands you may create macros without VR Viewer in the same way as for PHOTON USE commands A complete list of valid VR Viewer macro commands is given in Appendix VR Viewer Macro Commands below VR Viewer can also read a limited range of commands in the PHOTON command language This enables it to display images from PHOTON USE files which may be embedded in the Q1 Those compatible PHOTON commands are also listed at the end of the Appendix However if you need to change the default settings or draw streamlines it is recommended to use the VR Viewer macro function to save the macro commands first into vrvlog and then reduce its size by hand editing before adding it to a Q1 file 3 Running a macro The macro commands can be copied into the Q1 input file by placing them between the statements VRV USE and ENDUSE These two lines and all the macro lines must start in column 3 or more to ensure that they are treated as comments by the VR Editor Macros can be run as follows Press the MACRO button on the Hand set then Run Macro Click Ok and the selected file will be read and any macro commands in it will be executed IMAGE MACRO Functions dialog run The default file name is Q1 For each image there will be a text message window Click Ok to continue or Cancel to stop the macro Pressing F3 or clicking the F3 icon will run the currently selected macro file Appendix VR Viewer Macro Commands The commands set the state of the VR Viewer settings The screen image is updated when a PAUSE command is encountered or the end of the file is reached The image is the outcome of the final states of all the settings The commands making up the macro language can be divided into a number of groups Only those commands that change a default or change an existing setting need be placed in the macro file The individual commands can be shortened as long as the remaining part is unique Setting the File Name FILE name xyz name for BFC case Sets the name of the PHI and XYZ file to

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_enc/macro.htm (2016-02-15)
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  • MFM.HTM
    feature of PHOENICS which is used for the representation of some turbulent flow phenomena Its particular merit is that it permits calculation and use of the probability density functions which describe practically important properties of turbulence in an economical manner

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_enc/mfm.htm (2016-02-15)
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  • Multi-block Grid and Block Linkage Definition for GCV
    GCV and C are required parameters MBLjabcd is the name of the second link patch of a pair and def is a 3 character string The valid characters are selected from E W N S H L This string defines how the N E and H faces of the first block link to the second block The default natural link would be S W L i e North to South East to West and High to Low Examples follow E N Block 2 S W N H W Block 1 E N Block 3 S S L Block 1 2 MPATCH 1 MBL1 2 NORTH MPATCH 2 MBL2 1 WEST SPEDAT SET GCV MBL2 1 C WNL Block 1 3 MPATCH 1 MBL1 3 EAST MPATCH 3 MBL3 1 NORTH SPEDAT SET GCV MBL3 1 C LNE Block 2 3 MPATCH 2 MBL2 3 WEST MPATCH 3 MBL3 2 HIGH SPEDAT SET GCV MBL3 2 C SLE 6 Boundary and Source Locations The MPATCH command is also used to define the locations of any required boundary conditions sources blockages etc The format of the command is MPATCH i name type ixf ixl iyf iyl izf izl itf itl where i is the number of the block the source is located in name is a user specified unique identifying string up to 8 characters long type is any of the valid PHOENICS PATCH types ixf izl are the first and last cells in the local block co ordinates and itf itl are the first and last time step the source is to be active In order for the PHOENICS menu system to correctly identify the type of source especially inlets and outlets the following commands are required Inlets The patch name must start with the characters BFC and COVAL commands must exist for P1 U1 V1 and W1 MPATCH i BFCname type ixf ixl iyf iyl izf izl itf itl COVAL BFCname P1 FIXFLU GRND1 COVAL BFCname U1 ONLYMS GRND1 COVAL BFCname V1 ONLYMS GRND1 COVAL BFCname W1 ONLYMS GRND1 Outlets A COVAL command must exist for P1 MPATCH i name type ixf ixl iyf iyl izf izl itf itl COVAL name P1 1000 0 0 0 7 Example Q1 and grid files The files below show a simple 3 block case A picture of the case is shown here The block structure is L E Block 3 W L H L Block 2 E Block 1 W E W H H Blocks 1 2 and 1 3 are linked naturally West to East and Low to High whilst the link between 2 3 is unnatural a Low face is linked to a West face All blocks have a nominal grid of 2 2 2 There is an inlet of 1 m s in the X direction on the East face of Block 3 and an outlet to a relative pressure of 0 0 Pa on the West face of Block 2 The resulting Q1 is shown below Q1 TALK T RUN 1 1 Group 6 Body Fitted co ordinates BFC T NUMBLK 3 READCO i MPATCH 1 MBL1 3 LOW 2 3 1 2 2 2 1 1 MPATCH 3 MBL3 1 HIGH 2 3 1 2 2 2 1 1 MPATCH 1 MBL1 2 WEST 2 2 1 2 2 3 1 1 MPATCH 2 MBL2 1 EAST 2 2 1 2 2 3 1 1 MPATCH 2 MBL2 3 LOW 1 2 1 2 2 2 1 1 MPATCH 3 MBL3 2 WEST 2 2 1 2 1 2 1 1 SPEDAT SET GCV MBL3 2 C SLE Group 7 Variables STOREd SOLVEd NAMEd GCV T SOLVE P1 U1 V1 W1 STORE PRPS Group 13 Boundary conditions and special sources Fixed pressure boundary OUT7 for block 2 MPATCH 2 OUT WEST 1 1 1 2 2 3 1 1 COVAL OUT P1 1000 0 0 0 Inlet boundary INLET12 for block 3 MPATCH 3 BFCIN EAST 3 3 1 2 1 2 1 1 COVAL BFCIN P1 FIXFLU GRND1 COVAL BFCIN U1 ONLYMS GRND1 COVAL BFCIN V1 ONLYMS GRND1 COVAL BFCIN W1 ONLYMS GRND1 COVAL BFCIN UCRT 0 1 0 STOP Grid file i1 4 3 4 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 5 000000E 01 5 000000E 01 5 000000E 01 0 000000E 00 0 000000E 00 0 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 5 000000E 01 0 000000E 00 1 000000E 00 5 000000E 01 0 000000E 00 1 000000E 00 5 000000E 01 0 000000E 00 1 000000E 00 5 000000E 01 0 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 5 000000E 01 5 000000E 01 5 000000E 01 0 000000E 00 0 000000E 00 0 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 5 000000E 01 0 000000E 00 1 000000E 00 5 000000E 01 0 000000E 00 1 000000E 00 5 000000E 01 0 000000E 00 1 000000E 00 5 000000E 01 0 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 1 000000E 00 5 000000E 01 5 000000E 01 5 000000E 01 0 000000E 00 0 000000E 00 0 000000E 00 5 000000E 01 5 000000E 01 5 000000E 01 5 000000E 01 5 000000E 01 5 000000E 01 5 000000E 01 5 000000E 01 5 000000E 01 5 000000E 01 5 000000E 01 5 000000E 01 1 000000E 00 5 000000E 01 0 000000E 00 1 000000E 00 5

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_enc/mbgrids.htm (2016-02-15)
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  • MULTI-PHASE-FLOW SIMULATION in PHOENICS
    particulate phase for which the particle trajectories are computed as they move through a continuous fluid Method 1 IPSA for two iterpenetrating continua Click here Method 2 multiple inter penetrating continua the algebraic slip method Section 3 of the PHOENICS Encyclopaedia article on multi phase flow Click here for the start of the article When many phases are present it is impractical to solve full sets of Navier Stokes equations for all of them In this method therefore only one set of differential equations is solved to give the mixture mean velocities at each point and time Then separate sets of equations are solved one for each phase which govern its relative velocities i e their differences from the mean The latter equations are algebraic ones which are derived from the Navier Stokes equations by neglect of second order terms This entails that the relative velocities are computed by reference only to the local pressure gradients the body forces and the inter phase friction The volume fractions occupied by each phase at each point and time are calculated at the same time This method is referred to in the PHOENICS documentation as the algebraic slip method with the abbreviation ASLP Elsewhere in the scientific literature it is sometimes called the drift flux method It is embodied in the Advanced Multi Phase Flow option of PHOENICS and it makes use of the open source Fortran file GXASLP HTM Click here for a lecture on the algebraic slip method This method is especially useful for simulating sedimentation and other processes for example the separation of oil gas and water in a centrifuge An example of this kind now follows The axi symmetrical grid 38 50 The axis is along the lower edge of the picture border The flow is from right to left The cylindrical vessel is rotating at high speed so that the liquids are flung to the outside i e upward on the diagram Contours of pressure Velocity vectors Contours of air concentration Note the sharpness of the gas liquid interface This is of course realistic but not all numerical simulation schemes are capable of producing it Contours of total oil concentration Contours of light oil concentration Contours of heavier oil concentration Contours of heaviest oil concentration See also the following Applications Album entry Method 3 Separated i e free surface flows Section 4 of the PHOENICS Encyclopaedia article on multi phase flow Click here for the start of the article Method 3 treats the two or more fluids as a single fluid subject to discontinuities of density viscosity and composition These discontinuities i e the inter fluid surfaces are tracked as they move through the domain of interest by solution of the individual continuity equations of each fluid Three tracking procedures are available namely a the height of liquid method Click here for a lecture on HOL b the scalar equation method Click here for a lecture on SEM c the particle on surface method Click here for the

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_enc/multphfl.htm (2016-02-15)
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  • article PHOENICS encyclopaedia file TURBULENCE MODELS IN PHOENICS 7 MODELS FOR TWO PHASE FLOWS Contents Introduction Within Phase Diffusion Turbulent Diffusion of Phase Mass Two Equation K E Turbulence Model Enhancements for Bubble Induced Turbulence Enhancements for Turbulence Modulation due

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_enc/turmod/enc_tu7.htm (2016-02-15)
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