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  • FNxxx subroutines

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_enc/fnx.htm (2016-02-15)
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  • Forces on solid objects
    found in the Q1 This setting can also be made from the Output panel of the VR Editor Main Menu The default setting is F or Off For further details of what printout is provided please see the entry in TR326 An alternative to this is the use of the DRAG LIFT object A force balance is performed over the six faces of the volume described by the object The

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_enc/forces.htm (2016-02-15)
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  • Encyclopaedia Index FORTRAN CODING in GROUND subroutines inclusion by PHOENICS users Contents The programmability of PHOENICS Types of variables The F array The FNxxx functions wbs

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_enc/enc_for.htm (2016-02-15)
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    in the conventional single phase manner and the two fluids are accounted for through the specification of the physical properties density viscosity etc The applicability and limitations of these options can be summarized as follows The SEM technique deduces the interface position from the solution of a conservation equation for a scalar fluid marker variable and in this respect can suffer from numerical diffusion in coarse grids The SEM is applicable to unsteady incompressible flows only in one two or three dimensions It can simulate convoluted and overturning surfaces Since the SEM employs a fully explicit formulation it is constrained by the Courant criterion for time step increment for the stability of the solution The SEM generally works well for highly non orthogonal grids with NONORT set to TRUE It can also cope with heat transfer between the fluids and with conjugate heat transfer between the fluids and surrounding and immersed solids See the entry on S E M Scalar Equation Method for instructions on how to activate it The HOL method determines the location of the interface from the solution of the liquid balance equations The HOL method is applicable to both steady and unsteady incompressible isothermal flows in

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_enc/frees.htm (2016-02-15)
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    C20 C21 C22 C23 C24 C25 C26 C27 C28 C29 C30 C31 C32 1C33 C34 C35 The complete GRDLOC file may be inspected via POLIS path 1 4 In an unsteady flow problem the values of dependent variables which pertain to the PREVIOUS time step ie the so called old values are also FFV s Storage is automatically provided for these variables whenever i A SOLVE or SOLUTN command has required that the variable in question shall be solved for and ii the variable STEADY has been set to FALSE and iii a Y appears as the fifth argument of the relevant TERMS command either by direct setting or by default The command SOLVE TEM1 may also be employed so as to activate the direct solution for temperature as distinct from its indirect solution via enthalpy The name TEM1 is recognised within PHOENICS as necessitating the activation of sequences for multiplying by the specific heat see TEM1 for more details c Auxiliary variables FFV s may also be auxiliary variables which are STOREd but not SOLVEd ie those for which N no appears as the third argument of SOLUTN while Y yes appears as the second argument Porosities are of this kind as are those variables which users decide to introduce for their own purposes in GROUND The above example of a STORE command creates storage for two such variables namely HPOR and EFGH Auxiliary variables are not provided with field stores at the previous time step because EARTH has no need for them d Special auxiliary variables SAV s Also to be numbered with the FFV s are those special auxiliary variables SAVs which may be given FFV status for purposes of print out or under relaxation by the use of STORE name The complete list of names which

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_enc/fullf.htm (2016-02-15)
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  • FULLY-DEVeloped flows
    to be prescribed the following arbitarily named PATCH is introduced in the Q1 file PATCH PFORCEW VOLUME 1 NX 1 NY 1 NZ 1 1 COVAL PFORCEW FIXFLU GDPDZ where GDPDZ is the user defined axial pressure gradient If instead the user wishes to prescribe the mass flow rate then the following PIL commands need to be set in the Q1 file FDFSOL T USOURC T PATCH FDFW1DP VOLUME 1 NX 1 NY 1 1 1 1 COVAL FDFW1DP W1 prescribed mass flow rate GRND1 PHOENICS will then compute the axial pressure gradient automatically and print the result in the RESULT file For the case when the axial pressure gradient dp dz is specified the following formula is useful dp dz 0 5 f rho win win D 2 5 where win is the bulk velocity rho is the fluid density D is the hydraulic diameter and f is the friction factor given by f 64 Re 2 6 for laminar flow f 1 1 82 LOG10 Re 1 64 2 2 7 for turbulent flow in smooth tubes and by f 1 2 0 LOG10 0 5 eps 1 74 2 2 8 for turbulent flow in fully rough tubes Here Re is the Reynolds number based on hydraulic diameter and bulk velocity and eps is the relative roughness defined as the sand grain roughness height divided by the hydraulic diameter For non Couette flows the activation of the single slab solver requires several TERMS PATCH and COVAL settings therefore PHOENICS provides a short hand PIL command entitled FDSOLV which arranges all the necessary settings The first argument of this command differs according to whether the mass flow rate or axial pressure drop is to be specified by the user The second argument is used to specify the known quantity as follows FDSOLV FLOW prescribed mass flow rate or FDSOLV DPDZ prescribed axial pressure drop ii Heat and Mass Transfer The option to simulate thermally developed flow is activated by setting FDFSOL T in the Q1 file and introducing the following PATCH and COVAL statement PATCH patch name PHASEM 1 NX 1 NY 1 1 1 1 COVAL patch name H1 cp dTb dz GRND1 wherein the PATCH name FDFCHF for a constant heat flux boundary condition and FDFCWT for a constant wall temperature boundary condition For the latter the wall temperature must be defined by setting the VALue equal to the wall temperature rather than GRND1 For a constant heat flux boundary condition the user may wish to fix the temperature at the centre line of the duct so as to define a datum If the temperature is not fixed in this way the temperature variable can be interpreted as T Tw For both types of boundary condition the bulk temperature is printed in the RESULT file Finally it should be noted that the option to simulate thermally developed flow may be used irrespective of whether the automatic pressure adjustment is activated i e the user may still

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_enc/fdf.htm (2016-02-15)
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  • FUNCTion library for use in GROUND coding
    FN72 Y X1 A I Y A X1 I FN73 Y X1 A I Y A Y X1 I FN74 Y X1 A B C Y A X1 C 3 X1 C 2 B C X1 C B C 2 B C 3 FN75 X X1 A B C Y A abs X1 B C FN76 Y X1 X2 Y Y X1 X2 FN77 Y X1 X2 Y Y X1 X2 FN78 Y X1 X2 X3 A Y Y A X1 X2 X3 FN79 A X1 X2 X3 X4 A Patchwise sum of X1 X2 X3 X4 FN80 A X1 X2 A Patchwise sum of X1 X2 FN82 Y X1 A B Y AMAX1 Y A B X1 FN83 Y X1 A B Y AMIN1 Y A B X1 FN84 Y X1 X2 A B Y A X1 B X2 FN85 Y X1 X2 A B Y Y X1 A B X2 FN95 Y X1 A B C Y A X1 B C FN96 Y X1 X2 A Y Y X1 X2 A FN97 Y X1 X2 A B C Y A X1 X2 B C FN98 Y CM A B C superseded by GXMDOT FN99 Y X CF A B C D superseded by GXCFIP FN101 Y X A Y is a solution of x y 0 5 sin 2 0 y pi This is used for determining the half angle y subtended at the centre of a circular pipe by the surface of a liquid layer given the volume fraction X of the liquid The solution is obtained by iteration which ceases after 20 cycles or when Y changes by less than A whichever happens first FN102 Y X A B C y a b c 3 6666 sinx 3 cosx x 0 5 sin2x This calculates the hydrostatic force on the segment of the cross section of a circular sectioned pipe occupied by the heavier fluid The half angle at each cross section is X supplied by FN101 A is the acceleration due to gravity B is the density difference between the heavier and lighter fluids C is the radius of the pipe FN103 Y X IDIR Y X next X where IDIR 1 2 3 or for north south east or west FN104 Y X IPLUS Y X and X Y next This subroutine puts X into Y and then adds X here next refers to the north when IPLUS 1 and east when IPLUS NY FN105 Y X1 X2 IPLUS Y X1 unless X2 is negative in which case Y X1 shifted IPLUS cells from the current one For example if X2 refers to v velocities and IPLUS is 1 Y X1 in the North cell when v is negative FN107 Y X1 X2 X3 Y a weighted average of X1 and X2 the weighting factor depending on the ratio of the values of convection flux X3 to the time flux ie on the Courant number FN108 Y SUM which returns the patchwise sum of

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_enc/func.htm (2016-02-15)
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  • airfoil.htm
    November 1997 and May 1998 The flow is two dimensional incompressible inviscid and steady The PHOENICS version is 3 1 The airfoil in the VR Viewer A view of the grid Another view of the grid The pressure field Velocity

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_applic/movsol/airfoil/airfoil.htm (2016-02-15)
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