{"id":36085,"date":"2019-06-20T14:38:49","date_gmt":"2019-06-20T14:38:49","guid":{"rendered":"\/forum\/forums\/topic\/udf-compilation-and-interpretation-error\/"},"modified":"2019-06-20T14:38:49","modified_gmt":"2019-06-20T14:38:49","slug":"udf-compilation-and-interpretation-error","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/udf-compilation-and-interpretation-error\/","title":{"rendered":"UDF Compilation and Interpretation Error"},"content":{"rendered":"

Hi,<\/p>\n

<\/p>\n

I am facing errors while trying to do interpretation or compilation for a UDF in fluent.<\/p>\n

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I am simulating a 2D rectangular cavity with the following boundary conditions: adiabatic top layer, periodic side walls and rigid bottom with thermal heat flux and small random perturbations following this equation: dT\/dy= -exp(-h)+ epsilon*[rand(x)-0.5] , where rand is a one dimensional array of random numbers uniformly distributed in the range of [0,1].<\/p>\n

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I used a UDF to assign the heat flux and perturbation to the bottom layer. When I used interpretation of UDF, I get an error notifying that: srand: undeclared variable.<\/em><\/p>\n

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When trying to compile it, I get an error notifying that: The UDF library you are trying to load (libudf) is not compiled for parallel use on the current platform (win64<\/em>).nnThe system cannot find the file specified.<\/span><\/em> however, the<\/span> UDF source files are in the directory t<\/span>hat contains my case and data files.<\/span><\/p>\n

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Following the UDF I am using to set up the boundary condition at the bottom layer:<\/span><\/p>\n

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#include “udf.h”<\/p>\n

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#include “stdlib.h”            \/* srand and rand *\/<\/p>\n

<\/p>\n

#include “time.h”<\/p>\n

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#include “random.h”<\/p>\n

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#define RAND_MAX 32767<\/p>\n

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DEFINE_PROFILE(Temp_rand_pertubation_bottom,thread,index)<\/p>\n

<\/p>\n

{<\/p>\n

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 <\/p>\n

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real x[ND_ND]; \/* this will hold the position vector *\/<\/p>\n

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<\/p>\n

face_t f;<\/p>\n

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real time= CURRENT_TIME;<\/p>\n

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float h,E,r;<\/p>\n

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srand((unsigned)time(NULL));        \/*  this to specify a different random number at each cell *\/<\/p>\n

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k=0.6                \/* thermal conductivity *\/<\/p>\n

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T=300               \/* Temp in Kelvin *\/<\/p>\n

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h = 0.5; \/* cavity height  *\/<\/p>\n

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E= 0.01; \/* epsilon constant value *\/<\/p>\n

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  begin_f_loop_all(f,thread)<\/p>\n

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{<\/p>\n

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r= rand()\/float(RAND_MAX);       \/* r is a 1D array of random numbers uniformly distributed in the range of [0,1] *\/<\/p>\n

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F_CENTROID (x,f,thread);<\/p>\n

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F_PROFILE(f,thread,index) = k*T*(- exp(-h)+E*(r-0.5))\/h;         \/* apply random perturbation *\/<\/p>\n

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}<\/p>\n

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  end_f_loop_all(f,thread);<\/p>\n

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 <\/p>\n

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void srand(unsighned int seed);<\/p>\n

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}<\/p>\n

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 <\/p>\n

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<\/p>\n

To avoid these errors, please advice me whether my UDF need to be corrected or modified, or its something to do with fluent itself.<\/p>\n

<\/p>\n

 <\/p>\n

<\/p>\n

Many thanks<\/p>\n

<\/p>\n

Esra’a<\/p>\n","protected":false},"template":"","class_list":["post-36085","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_old_topic_id":["8257"],"_bbp_old_topic_author_name_id":["Anonymous"],"_bbp_old_is_topic_anonymous_id":["false"],"_bbp_old_closed_status_id":["publish"],"_bbp_author_ip":[null],"_bbp_old_sticky_status_id":["normal"],"_bbp_likes_count":["0","0"],"_btv_view_count":["2307"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["36085"],"_bbp_forum_id":["27796"],"_bbp_engagement":["199","22555","157480","163991"],"_bbp_voice_count":["4"],"_bbp_reply_count":["18"],"_bbp_last_reply_id":["89743"],"_bbp_last_active_id":["89743"],"_bbp_last_active_time":["2019-07-16 17:56:36"]},"test":"ehkh"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/36085","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics"}],"about":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/types\/topic"}],"version-history":[{"count":0,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/36085\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=36085"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}