Elmer Discussion Forum

Hi to everyone

I have a 3d system composed of a tube with inside a body and turbine blades. All the system is rotationsymmetric allong the y-axis. I defined a inlet of airstream with -2m/s in y direction, an outlet with no boudary conditions and a boundary condition with non slip walls. I would like to turn across the y-axis all the system with 600 RPM (rounds per minute). Is this possible with elmer and if yes - how?

I think that a lot of users have this problem. Would be nice to add it to the examples of elmer tutorial

I attach the emer gui files.

Please give me a help

Thanks,
Stefano

Hi Stefano

There is a test case (no GUI) named "RotatingFlow". It is just a simple 2D flow where the idea is to ensure that you can get the same solution by enforcing rotating by BCs and using another coordinate system and rotating the coordinate system. This results to an additional force.

So in this case you might work on the coordinate system of the turbine blades and set the BCs for the rotationally symmetric part when you now the angular velocity. I think this should work. What I'm more worried about is you rude mesh and the combination of probably quite high Re numbers you may want to study. Turbulence is not the strongest part of Elmer so you might want to approach the solution starting from small Re values.

-Peter

Thank You very much for Your fast response
I know that the mesh is rude I have also a fine mesh of all. As long that i don't have the right sif file i wanted to make the test for geting in rotation on a smaller mesh. I will look at the example hoping to come out You did a great programm and I realy aprechead it.