wall shear stress based on primary phase in eulerian multiphase model

Abishek · January 21, 2013, 06:16

hi. I am using the eulerian multiphase model to simulate flow boiling. To define some boiling parameters in my udf, i require to access the wall-shear stress based on liquid (primary) phase velocity gradient on walls. my simulation is 2D.

Based on suggestions on other posts in the forum, I have tried using the following syntaxes

1. NV_MAG(F_STORAGE_R_N3V(f,ptf[0],SV_WALL_SHEAR))/face_area
2. NV_MAG(F_STORAGE_R_N3V(f,ptf[0],SV_WALL_SHEAR)[0])/face_area

however, i find the usual ACCESS_VIOLATION error.

I am guessing that the syntax is incorrect somewhere, especially when applied to the 2D case. Any help in identifying the error is greatly appreciated.

domino · May 31, 2022, 13:15

Try to define first the correct pointer "pt_liq" to the correct thread t (mixture thread, wall thread, not cell adjacent to wall!) in your begin_f_loop(f,t)

pt_liq= THREAD_SUB_THREAD(t,0);
tau_w=NV_MAG(F_STORAGE_R_N3V(f,pt_liq,SV_WALL_SHEA R));

January 21, 2013, 06:16	wall shear stress based on primary phase in eulerian multiphase model	#1
Abishek New Member Join Date: Sep 2011 Posts: 11 Rep Power: 15	hi. I am using the eulerian multiphase model to simulate flow boiling. To define some boiling parameters in my udf, i require to access the wall-shear stress based on liquid (primary) phase velocity gradient on walls. my simulation is 2D. Based on suggestions on other posts in the forum, I have tried using the following syntaxes 1. NV_MAG(F_STORAGE_R_N3V(f,ptf[0],SV_WALL_SHEAR))/face_area 2. NV_MAG(F_STORAGE_R_N3V(f,ptf[0],SV_WALL_SHEAR)[0])/face_area however, i find the usual ACCESS_VIOLATION error. I am guessing that the syntax is incorrect somewhere, especially when applied to the 2D case. Any help in identifying the error is greatly appreciated. Last edited by Abishek; January 21, 2013 at 07:19.

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May 31, 2022, 13:15		#2
domino New Member Join Date: Sep 2010 Location: Germany Posts: 4 Rep Power: 16	Try to define first the correct pointer "pt_liq" to the correct thread t (mixture thread, wall thread, not cell adjacent to wall!) in your begin_f_loop(f,t) pt_liq= THREAD_SUB_THREAD(t,0); tau_w=NV_MAG(F_STORAGE_R_N3V(f,pt_liq,SV_WALL_SHEA R));