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February 21, 2012, 05:21 
Calculate the entering flow rate in each cell

#1 
Member
Join Date: Apr 2010
Posts: 53
Rep Power: 9 
Hi at all!
I am trying to find a way how to calculate the flow rate that enters or leaves a cell. In sum it should be zero but I like to find out a specific value for each cell of the domain. Does anyone has an idea how to approach this? Thank you very much in advance. 

February 21, 2012, 21:11 

#2  
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Ji Junjie
Join Date: Feb 2010
Location: Shanghai, China
Posts: 109
Rep Power: 10 
Quote:


May 30, 2012, 11:11 
problem trying to get the mass flow entering a cell

#3 
New Member
javiercran
Join Date: May 2012
Posts: 2
Rep Power: 0 
Hello,
I have tried to calculate the mass flow entering inside a cell (for a DEFINE_SOURCE macro) with a loop over the faces of the cell but I have problems of "noninteger subscript expression: unsigned char". This is my code #include "udf.h" #include <mem.h> DEFINE_SOURCE(theta_momentum,c,t,dS,eqn) { //near peak operating point real Ft; //Ft source term real T01; //Inlet Total temperature real T02; //Outlet Total temperature real cp; //variable which will store the specific heat of air real x[ND_ND]; //array for storing the centroid position real pi=3.1416; real omega=16043*2*pi/60; real r; face_t f; real massflow=0; real volume; Thread *f_thread; int n; c_face_loop(c,t,n)//line 21 the one which gives problems {f=C_FACE(c,t,n); f_thread = C_FACE_THREAD(c,t,n); if(F_FLUX(f,f_thread)>0)// only calculate the massflow entering {massflow=massflow+F_FLUX(f,f_thread); } } massflow=massflow*2*pi;//axisymmetric volume=C_VOLUME(c,t); T01=288.15; cp=1006; C_CENTROID(x,c,t);//we store in x the centroid position of each cell r=x[1];// the radial position is the ycoordinate of the cell centroid r = x[1]; T02=1.164*T01; Ft=massflow*cp*(T02T01)/(volume*omega*r); dS[eqn]=0; return Ft; } I need your help because I cant see the mistake I am doing. Regards 

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