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solving for Diffusivity
Posted Feb 26, 2016, 12:47 p.m. EST Fluid & Heat Version 5.1 2 Replies
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I am using the Transport of Dilute Species Module(time dependent study) for my project. In this module I am required to solve for N according to the equation N=-D∇c where D is the diffusivity and c is the concentration . Is there a way to solve for Diffusivity (D) if the other two parameters are known? Or is there another way to solve for it? , as the module will only let me solve for N.
Thank you
Thank you
2 Replies Last Post Mar 3, 2016, 8:11 a.m. EST
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Posted:
9 years ago
Hi,
Yes, you can. If you know N at steady state, then simply divide N by gradC to get D.
If not steady state, then you need to fit the flux (N) data using some minimization method (inverse analysis). Look for standard text book on how D is determined from column experiments.
Suresh
Yes, you can. If you know N at steady state, then simply divide N by gradC to get D.
If not steady state, then you need to fit the flux (N) data using some minimization method (inverse analysis). Look for standard text book on how D is determined from column experiments.
Suresh
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Posted:
9 years ago
I am not sure whether this is what you are tying to accomplish, but perhaps it is, so here goes.
It is possible with the Optimization module to solve what is known as an inverse problem, meaning that you ask for COMSOL to find the spatially-dependent material properties (or other inputs to the forward problem) such that the results of an analysis match as closely as possible with experimental data. This type of analysis is also referred to as "parameter estimation".
An example can be found at this link:
www.comsol.com/model/aquifer-characterization-4410
Jeff
It is possible with the Optimization module to solve what is known as an inverse problem, meaning that you ask for COMSOL to find the spatially-dependent material properties (or other inputs to the forward problem) such that the results of an analysis match as closely as possible with experimental data. This type of analysis is also referred to as "parameter estimation".
An example can be found at this link:
www.comsol.com/model/aquifer-characterization-4410
Jeff