UDF for removing the density in the flux term of UDS

Nadun19 · April 24, 2017, 20:10

Hi guys
I am trying to make a UDF that will remove the density term from the advective term in a user defined scalar. I have come up with the following code but it is giving me a segmentation error:

Code:

DEFINE_UDS_FLUX(overall_flux,f,t,i)
{
	real NV_VEC(velo), NV_VEC(A);
	NV_D(velo, =, F_U(f,t), F_V(f,t), F_W(f,t));
	F_AREA(A,f,t);
	return NV_DOT(velo,A);
}

I also tried this (what the ANSYS handbook has):

Code:

DEFINE_UDS_FLUX(overall_flux,f,t,i)
{
	real rho;
	rho = (C_R(F_C0(f,t),THREAD_T0(t)) + C_R(F_C1(f,t),THREAD_T1(t)))/2;
	return F_FLUX(f,t) / rho;
}

I have hooked the UDF correctly within the UDS box under flux function.

Thanks

PapDes · October 21, 2017, 14:30

Hi

Please were you able to remove the density term from the advective term for the UDS equation? And if you were able to do so, can you please share with how you did that?

Thanks

hosen · October 20, 2018, 17:58

hi Nadun.
could you remove density from UDS flux?
if yes, please explain how you could eliminate rho from UDS flux.
thanks

moji1990 · February 13, 2019, 06:38

Hi,
The segmentation error is maybe due to the fact that the velocity components are not available on the interior faces. I think they are only available at the boundary faces. You need to approximate the velocity on the interior faces by the values of corresponding variable stored at the adjacent cells centers.

April 24, 2017, 20:10	UDF for removing the density in the flux term of UDS	#1
Nadun19 New Member Nadun Palmada Join Date: Apr 2017 Posts: 15 Rep Power: 9	Hi guys I am trying to make a UDF that will remove the density term from the advective term in a user defined scalar. I have come up with the following code but it is giving me a segmentation error: Code: DEFINE_UDS_FLUX(overall_flux,f,t,i) { real NV_VEC(velo), NV_VEC(A); NV_D(velo, =, F_U(f,t), F_V(f,t), F_W(f,t)); F_AREA(A,f,t); return NV_DOT(velo,A); } I also tried this (what the ANSYS handbook has): Code: DEFINE_UDS_FLUX(overall_flux,f,t,i) { real rho; rho = (C_R(F_C0(f,t),THREAD_T0(t)) + C_R(F_C1(f,t),THREAD_T1(t)))/2; return F_FLUX(f,t) / rho; } I have hooked the UDF correctly within the UDS box under flux function. Thanks

October 21, 2017, 14:30	UDS advection term	#2
PapDes New Member Papsy Join Date: Feb 2017 Posts: 1 Rep Power: 0	Hi Please were you able to remove the density term from the advective term for the UDS equation? And if you were able to do so, can you please share with how you did that? Thanks

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October 20, 2018, 17:58		#3
hosen New Member hossein Join Date: Aug 2010 Posts: 3 Rep Power: 16	hi Nadun. could you remove density from UDS flux? if yes, please explain how you could eliminate rho from UDS flux. thanks

February 13, 2019, 06:38		#4
moji1990 New Member Mojtaba Join Date: Feb 2019 Posts: 1 Rep Power: 0	Hi, The segmentation error is maybe due to the fact that the velocity components are not available on the interior faces. I think they are only available at the boundary faces. You need to approximate the velocity on the interior faces by the values of corresponding variable stored at the adjacent cells centers.