{"id":388056,"date":"2024-10-03T20:51:45","date_gmt":"2024-10-03T20:51:45","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/user-defined-particle-wall-interaction-via-wall-film-how-many-max-fragments\/"},"modified":"2024-10-03T20:52:51","modified_gmt":"2024-10-03T20:52:51","slug":"user-defined-particle-wall-interaction-via-wall-film-how-many-max-fragments","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/user-defined-particle-wall-interaction-via-wall-film-how-many-max-fragments\/","title":{"rendered":"User Defined Particle-Wall Interaction via wall film: how many max. fragments?"},"content":{"rendered":"<p>&lt;p&gt;&lt;p&gt;#question Hi everyone, I have a very simple question. I am writing a user defined Fortran subroutine for particle-wall interaction via a wall film, and was referring to the following code documented in the page (8.6.3.1.3. User Defined Particle-Wall Interaction) of CFX Solver Modelling Guide. The question is about a single line in this code: &nbsp; REAL &nbsp; FACT, ANGLE, VEL_PT(3), DIAM_PT, NRATE_PT,&lt;br&gt;&nbsp; &nbsp; &nbsp;&amp; &nbsp; &nbsp; &nbsp; BRKUP_IND(3), CHILD_DIAM(3), CHILD_NRATE(3),&lt;br&gt;&nbsp; &nbsp; &nbsp;&amp; &nbsp; &nbsp; &nbsp; CHILD_COEF_N(3), CHILD_COEF_P(3), CHILD_MODE(3), DENS_FL &nbsp; &nbsp;&nbsp;&lt;br&gt;Is increasing the size of BRKUP_IND array allowed in CFX? I have tried doing BRKUP_IND(10), which means a particle can generate 10 fragments. The simulation ran without any error and a single particle did end up generating 10 fragments. However, the CFX engineers put this line on the page containing this code: &#8220;Note that a maximum of 4 child droplets may be generated with the child generation model.&#8221; What do they mean here? Maximum of 4 fragments by this code or in general? Although I tested with 1 particle, I am concerned it might not work for say a million particles and I might get an &#8220;overflow&#8221; error. Could anyone of you throw some light on this? I didn&#8217;t post on CFD Online because some smart people there deviate from answering the question and ask to run a simulation and check. In my case, I already did that, so I think AIS is the right place to ask. Thank you!&lt;br&gt;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;&lt;br&gt;&nbsp;#include &#8220;cfx5ext.h&#8221;&lt;br&gt;dllexport(pt_wall_splash)&lt;br&gt;&nbsp; &nbsp; &nbsp; SUBROUTINE PT_WALL_SPLASH (NLOC,NRET,NARG,RET,ARG,CRESLT,&lt;br&gt;&nbsp; &nbsp; &nbsp;&amp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; CZ,DZ,IZ,LZ,RZ)&lt;br&gt;CC&lt;br&gt;CD User routine: template for particle user routine&lt;br&gt;CC&lt;br&gt;CC &#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8211;&lt;br&gt;CC &nbsp; &nbsp; &nbsp; &nbsp;Input&lt;br&gt;CC &#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8211;&lt;br&gt;CC&lt;br&gt;CC &nbsp;NLOC &nbsp; &#8211; number of entities&lt;br&gt;CC &nbsp;NRET &nbsp; &#8211; length of return stack&lt;br&gt;CC &nbsp;NARG &nbsp; &#8211; length of argument stack&lt;br&gt;CC &nbsp;ARG &nbsp; &nbsp;&#8211; argument values&lt;br&gt;CC&lt;br&gt;CC &#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8211;&lt;br&gt;CC &nbsp; &nbsp; &nbsp;Modified&lt;br&gt;CC &#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8211;&lt;br&gt;CC&lt;br&gt;CC &#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8211;&lt;br&gt;CC &nbsp; &nbsp; &nbsp; &nbsp;Output&lt;br&gt;CC &#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8211;&lt;br&gt;CC&lt;br&gt;CC &nbsp;RET &nbsp; &nbsp;&#8211; return values&lt;br&gt;CC&lt;br&gt;CC &#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8211;&lt;br&gt;CC &nbsp; &nbsp; &nbsp; Details&lt;br&gt;CC &#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8211;&lt;br&gt;CC&lt;br&gt;CC======================================================================&lt;br&gt;C&lt;br&gt;C &#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&lt;br&gt;C &nbsp; &nbsp; Preprocessor includes&lt;br&gt;C &#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&lt;br&gt;C&lt;br&gt;#include &#8220;cfd_sysdep.h&#8221;&lt;br&gt;#include &#8220;cfd_constants.h&#8221;&lt;br&gt;C&lt;br&gt;C &#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&lt;br&gt;C &nbsp; &nbsp; &nbsp; &nbsp;Argument list&lt;br&gt;C &#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; INTEGER NARG, NRET, NLOC&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; CHARACTER*(4) CRESLT&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; REAL ARG(NLOC,NARG), RET(NLOC,NRET)&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; INTEGER IZ(*)&lt;br&gt;&nbsp; &nbsp; &nbsp; CHARACTER CZ(*)*(1)&lt;br&gt;&nbsp; &nbsp; &nbsp; DOUBLE PRECISION DZ(*)&lt;br&gt;&nbsp; &nbsp; &nbsp; LOGICAL LZ(*)&lt;br&gt;&nbsp; &nbsp; &nbsp; REAL RZ(*)&lt;br&gt;C&lt;br&gt;C=======================================================================&lt;br&gt;C&lt;br&gt;C &#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&lt;br&gt;C &nbsp; &nbsp;Executable Statements&lt;br&gt;C &#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&lt;br&gt;C&lt;br&gt;C=======================================================================&lt;br&gt;C&lt;br&gt;C &nbsp; &nbsp; Return variables:&lt;br&gt;C &nbsp; &nbsp; &#8212;&#8212;&#8212;&#8212;&#8212;&#8211;&lt;br&gt;C&lt;br&gt;C &nbsp; &nbsp; Child droplet breakup indicator &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; : RET(1,1)&lt;br&gt;C &nbsp; &nbsp; Child droplet diameter &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;: RET(1,5)&lt;br&gt;C &nbsp; &nbsp; Child droplet number rate &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; : RET(1,9)&lt;br&gt;C &nbsp; &nbsp; Child droplet normal coef of restitution &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;: RET(1,13)&lt;br&gt;C &nbsp; &nbsp; Child droplet parallel coef of restitution &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;: RET(1,17)&lt;br&gt;C &nbsp; &nbsp; Child droplet mode &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;: RET(1,21)&lt;br&gt;C&lt;br&gt;C &nbsp; &nbsp; Argument variables&nbsp;&lt;br&gt;C &nbsp; &nbsp; &#8212;&#8212;&#8212;&#8212;&#8212;&#8212;-&lt;br&gt;C&lt;br&gt;C &nbsp; &nbsp; Particle impact angle &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;: ARG(1,1)&lt;br&gt;C &nbsp; &nbsp; Particle velocity &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;: ARG(1,2)&lt;br&gt;C &nbsp; &nbsp; Particle diameter &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;: ARG(1,5)&lt;br&gt;C &nbsp; &nbsp; Particle number rate &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; : ARG(1,6)&lt;br&gt;C &nbsp; &nbsp; Fluid density &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;: ARG(1,7)&lt;br&gt;C&lt;br&gt;C &nbsp; &nbsp; We know that NLOC is 1 for the particle user source routines!!!!&lt;br&gt;C=======================================================================&lt;br&gt;C&lt;br&gt;C&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8211;&lt;br&gt;C &nbsp; &nbsp; Calculate the return variables&lt;br&gt;C&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8211;&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; CALL SPLASH (RET(1,1),RET(1,5),RET(1,9),RET(1,13),RET(1,17),&lt;br&gt;&nbsp; &nbsp; &nbsp;&amp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; RET(1,21),ARG(1,1),ARG(1,2),ARG(1,5),ARG(1,6),&lt;br&gt;&nbsp; &nbsp; &nbsp;&amp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; ARG(1,7))&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; END&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; SUBROUTINE SPLASH (BRKUP_IND,CHILD_DIAM,CHILD_NRATE,&lt;br&gt;&nbsp; &nbsp; &nbsp;&amp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; CHILD_COEF_N,CHILD_COEF_P,CHILD_MODE,&lt;br&gt;&nbsp; &nbsp; &nbsp;&amp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; ANGLE,VEL_PT,DIAM_PT,NRATE_PT,DENS_FL)&lt;br&gt;C&lt;br&gt;C &#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&lt;br&gt;C &nbsp; &nbsp;Preprocessor includes&lt;br&gt;C &#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&lt;br&gt;C&lt;br&gt;#include &#8220;cfd_sysdep.h&#8221;&lt;br&gt;#include &#8220;cfd_constants.h&#8221;&lt;br&gt;C&lt;br&gt;C&#8212;- Do not change these defines, they have to be consistent with what&lt;br&gt;C &nbsp; &nbsp; the solver uses&lt;br&gt;C&lt;br&gt;#define &nbsp; __regular_particle__ 1&lt;br&gt;#define &nbsp; &nbsp; &nbsp;__wall_particle__ 20&lt;br&gt;#define &nbsp; &nbsp; __pt_uf_get_data__ 1&lt;br&gt;#define &nbsp; &nbsp;__pt_uf_save_data__ 2&lt;br&gt;#define &nbsp; &nbsp; &nbsp; &nbsp;__pt_uf_iseed__ 1&lt;br&gt;#define &nbsp; &nbsp; &nbsp; &nbsp;__pt_uf_pmode__ 2&lt;br&gt;C&lt;br&gt;C &#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&lt;br&gt;C &nbsp; &nbsp; &nbsp; &nbsp;Argument list&lt;br&gt;C &#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; REAL &nbsp; FACT, ANGLE, VEL_PT(3), DIAM_PT, NRATE_PT,&lt;br&gt;&nbsp; &nbsp; &nbsp;&amp; &nbsp; &nbsp; &nbsp; BRKUP_IND(3), CHILD_DIAM(3), CHILD_NRATE(3),&lt;br&gt;&nbsp; &nbsp; &nbsp;&amp; &nbsp; &nbsp; &nbsp; CHILD_COEF_N(3), CHILD_COEF_P(3), CHILD_MODE(3), DENS_FL&lt;br&gt;C&lt;br&gt;C &#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&lt;br&gt;C &nbsp; &nbsp; &nbsp; &nbsp;Local variables&lt;br&gt;C &#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; REAL &nbsp; &nbsp;SIGMA, VISC_PT, R, SPEED_PT, ANGLE_DEG, ALFA, BETA,&lt;br&gt;&nbsp; &nbsp; &nbsp;&amp; &nbsp; &nbsp; &nbsp; &nbsp;GAMMA, VEL_NORM, OH, RE, K, M1M0&lt;br&gt;&nbsp; &nbsp; &nbsp; INTEGER ICHILD, ISEED, ACTION&lt;br&gt;C&lt;br&gt;C &#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&lt;br&gt;C &nbsp; &nbsp;Executable statements&lt;br&gt;C &#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&lt;br&gt;C&lt;br&gt;C=======================================================================&lt;br&gt;C &nbsp; &nbsp; Prologue&lt;br&gt;C=======================================================================&lt;br&gt;C&lt;br&gt;C&#8212;- Initialization&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; ICHILD = 0&lt;br&gt;C&lt;br&gt;C&#8212;- Get particle seed info (needed for random number generator)&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; ACTION = __pt_uf_save_data__&lt;br&gt;&nbsp; &nbsp; &nbsp; CALL USER_PARTICLE_INFO(ACTION,__pt_uf_iseed__,ISEED)&lt;br&gt;C&lt;br&gt;C&#8212;- Some material properties (water)&lt;br&gt;C &nbsp; &nbsp; &#8211;&gt; Surface tension coefficient&lt;br&gt;C &nbsp; &nbsp; &#8211;&gt; Particle viscosity&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; SIGMA &nbsp; = 0.0201&lt;br&gt;&nbsp; &nbsp; &nbsp; VISC_PT = 0.001&lt;br&gt;C&lt;br&gt;C&#8212;- Random number (required for deviation angle)&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; CALL GET_RANDOM(R,1,ISEED)&lt;br&gt;C&lt;br&gt;C=======================================================================&lt;br&gt;C &nbsp; &nbsp; Computation Section&lt;br&gt;C=======================================================================&lt;br&gt;C&lt;br&gt;C&#8212;- Particle velocity magnitude and impact angle&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; SPEED_PT &nbsp;= SQRT(VEL_PT(1)**2 + VEL_PT(2)**2 + VEL_PT(3)**2)&lt;br&gt;&nbsp; &nbsp; &nbsp; ANGLE_DEG = ANGLE*180.\/PI&lt;br&gt;C&lt;br&gt;C&#8212;- Ohnesorge and Reynolds number&nbsp;&lt;br&gt;C &nbsp; &nbsp; &#8211;&gt; Re, based on wall normal impact velocity!&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; VEL_NORM = SIN(ANGLE)*SPEED_PT&lt;br&gt;&nbsp; &nbsp; &nbsp; OH = VISC_PT\/SQRT(DENS_FL*DIAM_PT*SIGMA)&lt;br&gt;&nbsp; &nbsp; &nbsp; RE = DENS_FL*DIAM_PT*VEL_NORM\/VISC_PT&lt;br&gt;C&lt;br&gt;C&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8211;&lt;br&gt;C &nbsp; &nbsp; Precompute reflection angle&lt;br&gt;C&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8211;&lt;br&gt;C&lt;br&gt;C&#8212;- Impact angle, ALFA, average reflection angle, BETA. Add random&nbsp;&lt;br&gt;C &nbsp; &nbsp; deviation angle, GAMMA, if ALFA &lt; 15 deg.&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; ALFA &nbsp;= 90. &nbsp; &#8211; ANGLE_DEG&lt;br&gt;&nbsp; &nbsp; &nbsp; BETA &nbsp;= 61.88 + 0.326*ALFA&lt;br&gt;&nbsp; &nbsp; &nbsp; GAMMA = 17.6 &nbsp;&#8211; 0.18*ALFA&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; IF (ALFA .LT. 15.) BETA = BETA + (R-0.5)*GAMMA&lt;br&gt;C&lt;br&gt;C&#8212;- Compute K-value&lt;br&gt;C &nbsp; &nbsp; &#8211;&gt; Clip K to avoid overflow during m1\/m0 calculation&lt;br&gt;C &nbsp; &nbsp; &nbsp; &nbsp; (221^9.2133 = 3.9773E+21)&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; K = MIN(OH*RE**1.25,221.)&lt;br&gt;C&lt;br&gt;C&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8211;&lt;br&gt;C &nbsp; &nbsp; K &lt;= 57 -&gt; Particle deposited at wall&lt;br&gt;C&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8211;&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; IF (K .LE. 57) THEN&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; &nbsp; ICHILD = ICHILD + 1&lt;br&gt;&nbsp; &nbsp; &nbsp; &nbsp; BRKUP_IND(ICHILD) &nbsp; &nbsp;= 1.&lt;br&gt;&nbsp; &nbsp; &nbsp; &nbsp; CHILD_DIAM(ICHILD) &nbsp; = DIAM_PT&lt;br&gt;&nbsp; &nbsp; &nbsp; &nbsp; CHILD_NRATE(ICHILD) &nbsp;= NRATE_PT&lt;br&gt;&nbsp; &nbsp; &nbsp; &nbsp; CHILD_COEF_N(ICHILD) = 0.0&lt;br&gt;&nbsp; &nbsp; &nbsp; &nbsp; CHILD_COEF_P(ICHILD) = 0.0&lt;br&gt;&nbsp; &nbsp; &nbsp; &nbsp; CHILD_MODE(ICHILD) &nbsp; = __wall_particle__&lt;br&gt;C&lt;br&gt;C&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8211;&lt;br&gt;C &nbsp; &nbsp; &#8230; else partially reflected&lt;br&gt;C&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8211;&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; ELSE&lt;br&gt;C&lt;br&gt;C&#8212;- Mass fraction across reflection&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; &nbsp; M1M0 = 3.9869E-21*K**9.2133&lt;br&gt;C&lt;br&gt;C&#8212;- Reflected portion of particle&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; &nbsp; ICHILD = ICHILD + 1&lt;br&gt;&nbsp; &nbsp; &nbsp; &nbsp; BRKUP_IND(ICHILD) &nbsp; &nbsp;= 1.&lt;br&gt;&nbsp; &nbsp; &nbsp; &nbsp; CHILD_DIAM(ICHILD) &nbsp; = DIAM_PT*M1M0&lt;br&gt;&nbsp; &nbsp; &nbsp; &nbsp; CHILD_NRATE(ICHILD) &nbsp;= NRATE_PT&lt;br&gt;&nbsp; &nbsp; &nbsp; &nbsp; CHILD_COEF_N(ICHILD) = COS(BETA*PI\/180.)*SPEED_PT&lt;br&gt;&nbsp; &nbsp; &nbsp; &nbsp; CHILD_COEF_P(ICHILD) = SIN(BETA*PI\/180.)*SPEED_PT&lt;br&gt;&nbsp; &nbsp; &nbsp; &nbsp; CHILD_MODE(ICHILD) &nbsp; = __regular_particle__&lt;br&gt;C&lt;br&gt;C&#8212;- Deposited portion of particle&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; &nbsp; ICHILD = ICHILD + 1&lt;br&gt;&nbsp; &nbsp; &nbsp; &nbsp; BRKUP_IND(ICHILD) &nbsp; &nbsp;= 1.&lt;br&gt;&nbsp; &nbsp; &nbsp; &nbsp; CHILD_DIAM(ICHILD) &nbsp; = DIAM_PT*(1. &#8211; M1M0)&lt;br&gt;&nbsp; &nbsp; &nbsp; &nbsp; CHILD_NRATE(ICHILD) &nbsp;= NRATE_PT&lt;br&gt;&nbsp; &nbsp; &nbsp; &nbsp; CHILD_COEF_N(ICHILD) = 0.0&lt;br&gt;&nbsp; &nbsp; &nbsp; &nbsp; CHILD_COEF_P(ICHILD) = 0.0&lt;br&gt;&nbsp; &nbsp; &nbsp; &nbsp; CHILD_MODE(ICHILD) &nbsp; = __wall_particle__&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; ENDIF&lt;br&gt;C&lt;br&gt;C=======================================================================&lt;br&gt;C &nbsp; &nbsp; Epilogue&lt;br&gt;C=======================================================================&lt;br&gt;C&lt;br&gt;C&#8212;- Update ISEED in particle database with value computed in&nbsp;&lt;br&gt;C &nbsp; &nbsp; this routine&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; ACTION = __pt_uf_get_data__&lt;br&gt;&nbsp; &nbsp; &nbsp; CALL USER_PARTICLE_INFO(ACTION,__pt_uf_iseed__,ISEED)&lt;br&gt;C&lt;br&gt;&nbsp; &nbsp; &nbsp; END&lt;\/p&gt;&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-388056","topic","type-topic","status-publish","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t<!-- All in One SEO 4.9.10 - aioseo.com -->\n\t<meta name=\"description\" content=\"#question Hi everyone, I have a very simple question. I am writing a user defined Fortran subroutine for particle-wall interaction via a wall film, and was referring to the following code documented in the page (8.6.3.1.3. User Defined Particle-Wall Interaction) of CFX Solver Modelling Guide. The question is about a single line in this code:\" \/>\n\t<meta name=\"robots\" content=\"max-image-preview:large\" \/>\n\t<link rel=\"canonical\" href=\"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/user-defined-particle-wall-interaction-via-wall-film-how-many-max-fragments\/\" \/>\n\t<meta name=\"generator\" content=\"All in One SEO (AIOSEO) 4.9.10\" \/>\n\t\t<meta property=\"og:locale\" content=\"en_US\" \/>\n\t\t<meta property=\"og:site_name\" content=\"Ansys Learning Forum | Ansys Innovation Space\" \/>\n\t\t<meta property=\"og:type\" content=\"article\" \/>\n\t\t<meta property=\"og:title\" content=\"User Defined Particle-Wall Interaction via wall film: how many max. fragments? | Ansys Learning Forum\" \/>\n\t\t<meta property=\"og:description\" content=\"#question Hi everyone, I have a very simple question. I am writing a user defined Fortran subroutine for particle-wall interaction via a wall film, and was referring to the following code documented in the page (8.6.3.1.3. User Defined Particle-Wall Interaction) of CFX Solver Modelling Guide. The question is about a single line in this code:\" \/>\n\t\t<meta property=\"og:url\" content=\"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/user-defined-particle-wall-interaction-via-wall-film-how-many-max-fragments\/\" \/>\n\t\t<meta property=\"article:published_time\" content=\"2024-10-03T20:51:45+00:00\" \/>\n\t\t<meta property=\"article:modified_time\" content=\"2024-10-03T20:52:51+00:00\" \/>\n\t\t<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n\t\t<meta name=\"twitter:title\" content=\"User Defined Particle-Wall Interaction via wall film: how many max. fragments? | Ansys Learning Forum\" \/>\n\t\t<meta name=\"twitter:description\" content=\"#question Hi everyone, I have a very simple question. I am writing a user defined Fortran subroutine for particle-wall interaction via a wall film, and was referring to the following code documented in the page (8.6.3.1.3. User Defined Particle-Wall Interaction) of CFX Solver Modelling Guide. 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I am writing a user defined Fortran subroutine for particle-wall interaction via a wall film, and was referring to the following code documented in the page (8.6.3.1.3. User Defined Particle-Wall Interaction) of CFX Solver Modelling Guide. 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