|July 14, 2011, 16:53||
Turbulence boundary conditions
Join Date: Jan 2011
Location: Boston University
Posts: 61Rep Power: 4
I created a half laval nozzle geometry and run air through it from one side to the other. Initially I ran a laminar simulation and found out that results tend to get quite turbulent. I'm now at the stage where I want to implement the k-epsilon model for turbulence.
The trouble I'm having is that when I run the simulation I start to get nonsensical velocity, pressure and temperature profiles e.g. I start getting negative pressures and velocities as high has 10^24 m/s. This is because I don't understand the K-epsilon boundary conditions well enough.
I am attaching my case file, can anybody give me any pointers as to how I should change the boundary conditions file to get reasonable results? The files P,T,U are ok, it's the rest of them that I don't understand. It's quite possible that I put the wrong bc's.
I should point out that in the laminar case, I specify high pressure at the inlet and lower pressure at the velocity, and that's how flow develops.
I am also attaching a picture of the results from the laminar simulation just so you know what the profiles look like. Any help would be greatly appreciated.
|July 16, 2011, 03:43||
k-epsilon bc settings
Join Date: Jun 2011
Location: Neubiberg 85579, Munich, Germany
Posts: 2Rep Power: 0
I am working on the impinging jets and also facing the same problem that I donít really know how to set the k-epsilon boundary conditions, how to calculate the k, omega, epsilon, kqwallfunction, omegawallfunction, nutwallfuction. I appreciate if somebody gives a detailed answer so that a basic understanding would be developed.
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