CFD Online Discussion Forums - Check particle impaction with User Fortran

By now, I found a way to determine if a particle touches the surface of an oscillating cylinder.

I use this User Fortran Code and put it into the file 'pt_termination.F':

Code:

#include "cfx5ext.h" 

dllexport(pt_termination) 

      SUBROUTINE PT_TERMINATION (NLOC,NRET,NARG,RET,ARG,CRESLT, 

     &                            CZ,DZ,IZ,LZ,RZ) 

CC 

CD User routine: template for particle user termination routine 

CC 

CC -------------------- 

CC        Input 

CC -------------------- 

CC 

CC  NLOC   - number of entities 

CC  NRET   - length of return stack 

CC  NARG   - length of argument stack 

CC  ARG    - argument values 

CC 

CC -------------------- 

CC      Modified 

CC -------------------- 

CC 

CC -------------------- 

CC        Output 

CC -------------------- 

CC 

CC  RET    - return values 

CC 

CC -------------------- 

CC       Details 

CC -------------------- 

CC 

CC====================================================================== 

C 

C ------------------------------ 

C     Preprocessor includes 

C ------------------------------ 

C 

#include "cfd_sysdep.h" 

#include "cfd_constants.h" 

C 

C ------------------------------ 

C        Argument list 

C ------------------------------ 

C 

      INTEGER NARG, NRET, NLOC 

C 

      CHARACTER*(4) CRESLT 

C 

      REAL ARG(NLOC,NARG), RET(NLOC,NRET) 

C 

      INTEGER IZ(*) 

      CHARACTER CZ(*)*(1) 

      DOUBLE PRECISION DZ(*) 

      LOGICAL LZ(*) 

      REAL RZ(*) 

C 

C======================================================================= 

C 

C --------------------------- 

C    Executable Statements 

C --------------------------- 

C 

C======================================================================= 

C 

C     Return variables: 

C     ----------------- 

C 

C     Particle fate                                        : RET(1,1) 

C 

C     Argument variables  

C     ------------------- 

C 

C     Particle mean diameter                               : ARG(1,1) 

C     Particle position                                    : ARG(1,2:4)

C     Cylinder x-position                   : ARG(1,5)

C     Cylinder y-position                   : ARG(1,6) 

C 

C     We know that NLOC is 1 for the particle user source routines!!!! 

C======================================================================= 

C 

C----------------------------------------------------------------------- 

C     Calculate the return variables 

C----------------------------------------------------------------------- 

C 

      CALL USER_FATE (RET(1,1),ARG(1,1),ARG(1,2),ARG(1,5),ARG(1,6)) 

C 

      END 

 

      SUBROUTINE USER_FATE (FATE,DIA,PPOS,CPOSX,CPOSY) 

C 

C --------------------------- 

C    Preprocessor includes 

C --------------------------- 

C 

#include "cfd_sysdep.h" 

#include "cfd_constants.h" 

C 

C ------------------------------ 

C        Argument list 

C ------------------------------ 

C 

      REAL               FATE, DIA, PPOS(3), CPOSX, CPOSY 

      REAL               CYLRAD, PRAD 

      REAL               CONTACT 

C 

C ------------------------------ 

C        Local variables 

C ------------------------------ 

C 

      REAL               DEAD, ALIVE 

C ------------------------------ 

C    Executable statements 

C ------------------------------ 

C 

      DEAD  = 0. 

      ALIVE = 1.  

C 

      CYLRAD = 0.005  

C 

C---- Particle starts as alive 

C 

      FATE = ALIVE 

C 

C---- Calc particle radius 

      PRAD = ((CPOSX-PPOS(1))**2 + (CPOSY-PPOS(2))**2)**0.5 

      CONTACT = CYLRAD - (PRAD - DIA/2.0) 

C 

C---- Check if user defined criterion was exceeded, stop particle 

C     --> Set particle mode to __dead__ 

C 

      IF (CONTACT.GT.0.0) THEN 

        FATE = DEAD 

      ENDIF 

C 

      END

In CFX I create a 'Particle User Routine', which uses the output of the F-file compilation. In case of an oscillating cylinder, you need to define the cylinder coordinates as two 'Additional Variables', called 'Xcyl' and 'Ycyl' (Varible Type = Unspecified, Units = [m], Tensor Type = Scalar). Now, these variables can be selected from 'Default Domain > Fluid Models > Additional Variable Models > Additional Variable'. You define both variables with an 'Algebraic Equation' with is for 'Xcyl'

Code:

rbstate(Position X)@Rigid Body Cylinder

and 'Ycyl'

Code:

rbstate(Position Y)@Rigid Body Cylinder

Now comes the crucial part: The in- and output arguments of the User Fortran need to be defined with a 'Particle User Termination Criteria', however, this can not be selected in the 'Particle Control' Panel of the CFX GUI. The 'Particle User Termination Criteria' needs to be defined using two seperate CCL-files, 'pt_term.ccl' and 'pt_extra.ccl'. There is the contents:
pt_term.ccl: (make sure the 'Library Path' is set corretly)

Code:

LIBRARY: 

  USER ROUTINE DEFINITIONS: 

    USER ROUTINE: termination 

      Calling Name = pt_termination 

      Library Name = pt_termination 

      Library Path = /work/simulations/test/part_capt/oscillation_capture 

      Option = Particle User Routine 

    END 

  END 

END 

FLOW:  

  SOLVER CONTROL:  

    Turbulence Numerics = First Order 

    ADVECTION SCHEME:  

      Option = High Resolution 

    END 

    CONVERGENCE CRITERIA:  

      Conservation Target = 0.01 

      Residual Target = 1.E-4 

      Residual Type = MAX 

    END 

    DYNAMIC MODEL CONTROL:  

      Global Dynamic Model Control = On 

    END 

    PARTICLE CONTROL:  

      PARTICLE INTEGRATION:  

        Option = Forward Euler 

      END 

      PARTICLE TERMINATION CONTROL: 

        Maximum Tracking Time = 10 [s] 

        Maximum Tracking Distance = 10 [m] 

        Maximum Number of Integration Steps = 100000 

        FLUID: Particle 

          PARTICLE USER TERMINATION CRITERIA: 

            Particle User Routine = termination 

            Argument Variables List = \ 

              Particle.Mean Particle Diameter,\ 

              Particle.Particle Position,\

          Xcyl,\

          Ycyl 

            Particle User Fate Return Variables List = \ 

              Particle Fate 

          END 

        END 

      END 

    END 

  END 

END

pt_extra.ccl:

Code:

RULES: 

  SINGLETON: PARTICLE TERMINATION CONTROL 

    Description = Sets details of the particle tracking integration \ 

                  algorithm. 

    Solver Name = PT_TERM_CTRL 

    Optional Parameter List = \ 

      Maximum Tracking Time, \ 

      Maximum Tracking Distance, \ 

      Maximum Number of Integration Steps, \ 

      Minimum Diameter, \ 

      Minimum Total Mass 

    Editable Option = True 

    Optional Child List = \ 

      MASS FRACTION LIMITS, \ 

     FLUID 

  END 

 

 OBJECT: FLUID 

   Description = This object encloses fluid-specific models and data. 

   # 

   # ...Context....   ...Allowed Contents......... 

   # DOMAIN           FLUID MODELS, SOLVER CONTROL 

   # SUBDOMAIN        SOURCES, BULK SOURCE DISTRIBUTION 

   # BOUNDARY         BOUNDARY CONDITIONS 

   # INITIALISATION   INITIAL CONDITIONS 

   # 

   Solver Name = FL 

   Object Name Restriction = CEL 

   Optional Child List =  \ 

     ADDITIONAL VARIABLE, \ 

     COMBUSTION MODEL, \ 

     COMPONENT, \ 

     DILATATIONAL STRESS, \ 

     ELECTROMAGNETIC MODEL, \ 

     FLUID BUOYANCY MODEL, \ 

     HEAT TRANSFER MODEL, \ 

     KINETIC THEORY MODEL, \ 

     SOLID PRESSURE MODEL, \ 

     SOLID BULK VISCOSITY, \ 

     SOLID SHEAR VISCOSITY, \ 

     THERMAL RADIATION MODEL, \ 

     TURBULENCE MODEL, \ 

     TURBULENT WALL FUNCTIONS, \ 

     WALL SLIP MODEL, \ 

     EROSION MODEL, \ 

     NUCLEATION MODEL, \ 

     INITIAL CONDITIONS, \ 

     BOUNDARY CONDITIONS, \ 

     SOURCES, \ 

     BULK SOURCE DISTRIBUTION, \ 

     SOLVER CONTROL, \ 

     INJECTION CONDITIONS, \ 

     PARTICLE ABSORPTION, \ 

     PARTICLE ROUGH WALL MODEL, \ 

     PARTICLE USER TERMINATION CRITERIA 

 END 

 

 SINGLETON: PARTICLE USER TERMINATION CRITERIA 

    Description = Controls user defined particle fate 

    Solver Name = USR_TERM_CTRL 

#   Context Rule = Option 

#   Allowed Option List = \ 

#     User Defined 

#   Essential Parameter List = \ 

#     Option 

#   CONTEXT: User Defined 

      Essential Parameter List = \ 

        Particle User Routine, \ 

        Argument Variables List, \ 

        Particle User Fate Return Variables List 

#   END 

  END 

 

  PARAMETER: Particle User Fate Return Variables List 

    Parameter Type = String List 

    Solver Name = CVAR_RET 

    Allowed String List = \ 

        Particle Fate 

  END 

END

These need to be added to the CFX solver call. From the command line, you add:

Code:

-ccl pt_term.ccl -ccl pt_extra.ccl

to your regular function call.

Now, after each time step. The solver writes the number of particles, which touched the surface of the cylinder in the 'Particle Diagnostics'.