[danny123]

Hello,

I am using the AMI feature of OF 2.1 to simulated a special mixer type application. I have my grid (using blockmesh separate on rotor and stator area and merging them) and I can view it and run pimpledymfoam on the case. After 8 ms of total time of 6 s, OpenFoam stalls on a stackoverflow. So, I decided to use smaller time steps, which works, but the performance is that slow, that calculation will take 20 years to finish for one case. This is too slow for me. I found out that the first couple 1/1000 s are calculated rather quickly, then the time steps become very small. My idea now is the following: maybe it is not good to start the rotor at nominal speed, but use a ramp or better some cos function, whereas the speed starts at zero and ends at nominal speed and having zero gradient at start and at the end of the ramp.

I looked into the forum for ramp programming, but they all refer to parameters like U, p and the like, not of the angular speed. This angular speed is defined in dynamicMeshDict as "radialVelocity" parameter (kind of confusing sind an angular speed is not a radial velocity). The unit is deg/s thus I think this is the angular speed. There is no reference to "fixedvalue", as one would see it in U or the like, which I could change to "table" or "polynominal" or the like.

Is there anybody who has an idea?

Regards,

Daniel