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-   -   Upwind Schemes in Non-Newtonian Flows (http://www.cfd-online.com/Forums/main/14965-upwind-schemes-non-newtonian-flows.html)

ferreira March 23, 2008 04:57

Upwind Schemes in Non-Newtonian Flows
 
Hi Dear Friends,

My question is this one:

Why it is need to apply high resolution upwind scheme in Non-Newtonian and Viscoelastic flows? I think these problems are not dominated by advection!!!

Ferreira

ag March 24, 2008 08:54

Re: Upwind Schemes in Non-Newtonian Flows
 
Possible reasons

1. Non-Newtonian simply means that the constitutive relationship between stress and velocity is not the linear model that we use in the NS equations for closure. That has no bearing on whether the flow is advection-dominated, i.e. non-Newtonian flows can be just as advection-dominated as Newtonian flows.

2. If a flow is highly visco-elastic, then it may not be advection dominated. But if I am a researcher who has a working upwind code, and I need to generate a code which will work for a visco-elastic flow, then which makes more sense - create an entirely new code, or swap out the module that I use to compute stress as a function of velocity? If I choose the latter, I have a code that requires less validation, and it will remain valid even for those visco-elastic flows that will have areas of non-negligible advection (which may be more often than you think).


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