|April 5, 2009, 10:13||
UDF compute residence time session Id 619
Join Date: Apr 2009
Posts: 14Rep Power: 9
I am looking for UDF to compute residence time with the session ID 619. Can anyone post the code when u have.
Thanks in advance
|April 6, 2009, 05:31||
Join Date: Mar 2009
Posts: 133Rep Power: 9
Here it is:
* UDF to compute fluid residence time
* by William Wangard, Ph.D.
* Fluent, Inc.
* This UDF requires at least 1 UDS to be defined
* At inlet, define UDS (value) = 0
* UDS will have units of time and represent approximate residence time
* of fluid in domain
* Diffusivity of scalar should be small to reduce diffusion i.e. 1E-5
real source = C_R(c,t);
dS[eqn] = 0.0;
|January 21, 2016, 08:25||
Join Date: Aug 2013
Posts: 38Rep Power: 5
Hi CFD friends!
I am trying to compute residence time contours using this kind of UDF.
My questions are the following:
1. Changing the mesh, then the residence time contours change (at least the maximum of residence time). I guess this is not desirable. Anybody has an idea about why this is happening? I realized that mesh cells appear in the function...
I am wondering if achieving mesh independent results will fix this, it's to said, max_residence_time tends to real_max_residence_time as cell_size tends to zero
If not, I am not understanding the value of this UDF as residence time will be mesh-dependent...
2. Which values should I use for Schmidt number and mass diffusivity for water?
3. When I got convergent results, I just solve for the defined scalar in steady state. Is unsteady solution needed? In other words, have I switch to unsteady model just for solving the scalar transport?
Thanks in advance for all your answers. I am a beginner in UDF...
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