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Inviscid flow with shocks/ Residual convergence

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Old   October 23, 2013, 07:47
Default Inviscid flow with shocks/ Residual convergence
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Anna
Join Date: Jun 2012
Location: Finland
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Hullo!

I would require a bit of help in the pre-processing of flow scenario in a dilating duct. In order to simulate inviscid flow I've set the its properties to laminar and all wall boundary conditions to free-slip, but I've also heard from different sources that one should set the viscosity as naught - a precedure that makes sense in theory but seems difficult in practice. If I would set the value of viscosity to naugt that would make my Reynolds number infinite, which would undoubtedly lead to complications further on. As a high Reynolds number implies turbulent flow, I'm afraid that using all settings mentioned above would make the system fully unphysical. What would, in your opinion, be the best way to achieve inviscid flow? A further complication will arise due to shocks in the flow because they would (in real life) affect the local viscosity values in the flow. Is the assumption of inviscid flow even justified in a problem involving a pseudo-shock?

The task that I'm working on is actually only a pre-phase to viscous shock train simulation, something that should provide me with a little bit of insight before I go and simulate the actual, viscous case. Having done something similar before, I remember I had a lot of trouble in trying to get the residuals to converge under the value of about 10^-6. Furthermore I remember I could not access Residual Contour data in CFX-Post when trying to control where the problem areas in the flow were. I was (and will be) using a BSL turbulence model if I'm not terribly mistaken. Could it be that CFX-Post simply doesn't offer Residual Contour data for this model or might I have made a mistake of some sort in CFX-Pre? I'm using the Air Ideal Gas model with total energy.

Cheers for helping, if you need any more information just let me know and I'll provide!
Cheerio!
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