distance between every two faces

yoollooz · January 6, 2013, 02:34

i want to calculate below formula too.how can i write udf?
please help me.
s[i][j]=(exp(k*s)*(A[i].r)*(A[j].r))/(4*s)
k=constant
s=NV_MAG(r)
A[i] , A[j] = Area
r= distance between face A[i] and A[j]
how can i calculate this formula for all faces in domain?

msaeedsadeghi · January 6, 2013, 08:08

It may not be possible. What is the meaning of previous face? You should modify the algorithm.

yoollooz · January 6, 2013, 11:15

i want to write exchange factor for radiation by zone method and i have to compute the surface to surface exchange factor between every two surfaces, surface to gas exchange factor between every face and gas cell , and gas to gas exchange factor between every two gas cell.
formula for surface to surface exchange factor between surfaces i and surface j is:
ss[i][j]=(exp(-k*s)*(A[i].r)*(A[j].r))/(4*s)
k=constant
A[i] =surface i area
A[j] = surface j area
r=distance vector between face A[i] and face A[j]
s= magnitude of distance between face A[i] and A[j]

January 6, 2013, 02:34	distance between every two faces	#1
yoollooz New Member morteza Join Date: Jan 2013 Posts: 8 Rep Power: 13	i want to calculate below formula too.how can i write udf? please help me. s[i][j]=(exp(ks)(A[i].r)(A[j].r))/(4s) k=constant s=NV_MAG(r) A[i] , A[j] = Area r= distance between face A[i] and A[j] how can i calculate this formula for all faces in domain? Last edited by yoollooz; January 6, 2013 at 07:59.

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January 6, 2013, 08:08		#2
msaeedsadeghi Senior Member SSL Join Date: Oct 2012 Posts: 226 Rep Power: 14	It may not be possible. What is the meaning of previous face? You should modify the algorithm.

January 6, 2013, 11:15		#3
yoollooz New Member morteza Join Date: Jan 2013 Posts: 8 Rep Power: 13	i want to write exchange factor for radiation by zone method and i have to compute the surface to surface exchange factor between every two surfaces, surface to gas exchange factor between every face and gas cell , and gas to gas exchange factor between every two gas cell. formula for surface to surface exchange factor between surfaces i and surface j is: ss[i][j]=(exp(-ks)(A[i].r)(A[j].r))/(4s) k=constant A[i] =surface i area A[j] = surface j area r=distance vector between face A[i] and face A[j] s= magnitude of distance between face A[i] and A[j]