# UDF extern variable - mean time moment coefficient

 Register Blogs Members List Search Today's Posts Mark Forums Read November 14, 2009, 07:51 UDF extern variable - mean time moment coefficient #1 Senior Member   Herman Join Date: Nov 2009 Posts: 122 Rep Power: 15 Hi ! I wanna calculate the mean time moment coefficient in an unsteady simulation. I write a function as DEFINE_EXECUTE_AT_END in order to have the moment coefficient at the end of time step, and the program sum cm every time step. So I have the sum of every cm for all time step at the end of simulation. The problem is: how can I declare the variable "sum_cm" as an extern variable, in order to divide it at the end of the simulation? I try to write the next program: #include "udf.h" #include "extfile.h" DEFINE_EXECUTE_AT_END(moment_coefficient) { real NV_VEC(A); real moment = 0., x_nodo = 0., y_nodo = 0.; int IDblades = 10, IDblades_sh = 14; int n; face_t f,f_sh; Thread *f_thread, *f_thread_sh; Domain *d; Node *node; d = Get_Domain(1); /* Default Interior ID */ if(NULL == d) printf("Something wrong with your domain id!\n"); f_thread = Lookup_Thread(d, IDblades); f_thread_sh = Lookup_Thread(d,IDblades_sh); if(NULL == f_thread) printf("Something wrong with your face id!\n"); if(NULL == f_thread_sh) printf("Something wrong with your face shadow id!\n"); /*if(!BOUNDARY_FACE_THREAD_P(f_thread)) Error("Something wrong with your face id!\n"); */ begin_f_loop(f,f_thread) { F_AREA(A,f,f_thread); f_node_loop(f,f_thread,n) { node = F_NODE(f,f_thread,n); x_nodo = NODE_X(node); y_nodo = NODE_Y(node); moment += F_P(f,f_thread) * A * x_nodo - F_P(f,f_thread) * A * y_nodo; } } end_f_loop(f,f_thread) begin_f_loop(f_sh,f_thread_sh) { F_AREA(A,f_sh,f_thread_sh); f_node_loop(f_sh,f_thread,n) { node = F_NODE(f_sh,f_thread,n); x_nodo = NODE_X(node); y_nodo = NODE_Y(node); moment += F_P(f_sh,f_thread_sh) * A * x_nodo - F_P(f_sh,f_thread_sh) * A * y_nodo; } } end_f_loop(f_sh,f_thread_sh) moment = moment/2; int_moment += moment; printf("\n MOMENT = %g \n", moment); printf("\n INT MOMENT = %g \n", int_moment); } where the extfile.h is the following: #include "udf.h" extern real int_moment = 0.; I compile it as "compiled UDF", but Fluent reports some errors, and the most dangerous is the following: moment_coefficient.c:2:21: error: extfile.h: No such file or directory CAN ANYBODY HELP ME?!  Thread Tools Search this Thread Show Printable Version Email this Page Search this Thread: Advanced Search Display Modes Linear Mode Switch to Hybrid Mode Switch to Threaded Mode Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are Off Pingbacks are On Refbacks are On Forum Rules Similar Threads Thread Thread Starter Forum Replies Last Post irishdave OpenFOAM Running, Solving & CFD 32 June 16, 2021 07:55 skabilan OpenFOAM Running, Solving & CFD 14 December 17, 2019 00:12 prasad84 FLUENT 0 October 16, 2009 15:27 carsten OpenFOAM Bugs 11 September 12, 2008 12:16 m9819348 OpenFOAM Running, Solving & CFD 7 October 27, 2007 01:36