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Null drag coefficient - nuSgs and nuTilda

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Old   September 9, 2013, 09:07
Default Null drag coefficient - nuSgs and nuTilda
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Hello everybody!!

I use OpenFOAM since just a couple of weeks and I have problems with a simulation. I am trying to simulate a sphere inside a fluid at different Re.

I want to use different models to learn about the differences and so, but at the moment I am just trying to fit the results that I get regarding the drag coefficient.

I have set up the case to Re 50, 500, 5000, 50000 and 25000 using a DES-Spalart Allmaras model.

The first two cases with the low Reynold numbers worked properly and got close-enough Cd; in the rest, the Drag Coefficient seems to go asintotic to 0, no matter how long OpenFoam iterates...

In order to find the mistake I have done, I wanted to check the evolution of what in Fluent is called "Modified Turbulent Viscosity", but I didn't find it to compare. What I can check in ParaView are nuTilda and nuSgs, but nuTilda only is defined in the different patches always as zero, and I don't know what nuSgs is...

Any advice would be very helpful. Thanks!
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