I am modelling a hydro-electric turbine and am currently in the processes of finding the optimal tip speed ratio of the turbine however the results i am getting are wrong. As this is a drag based turbine the TSR shouldn’t exceed 1 however this is not the case for me. As the angular velocity increases so does the power. From research this should take the form of a parabola. i have followed all the tutorials that are related to this on SimScale so any other help would be greatly appreciated.
Hello fsinclair,
from what I can see your residuals are quite oscilating.
Therefore can you please try to have a transient run making sure, that there are no transient effects occurring in the simulation.
Also have you done some mesh independency analysis as well as wake refinement analysis?
This might be some reason for the inaccurate results.
Best regards Sebastian
Hi fsinclair,
Firstly I’m no hydro turbine or CFD expert like SBlock, just a novice, so ignore my comments if they seem misguided.
When I look at you model, the convergence residual seems good & ok, ie consistent, smooth and decreasing (red/omega) to a low value, besides a few other good trends.
So then I looked at your turbine rotation which may be incorrect? Simscale uses the Right Hand Thumb rotational rule, ie " if you curl the fingers of your right hand around with the direction of the rotational motion, your thumb will point in the direction of rotation, which will be along the axis of rotation"
The current model has a forced rotation of 12 rad/s rotating in the red arrow direction, whereas I think it should be imparting a rotation in the green direction?
So I’d suggest possibly using -12 rad/s instead of the current +12 rad/s ?
I may be barking up the wrong tree, but all the best and good luck with your CFD, I do like the rotor/turbine sketch 
Kind regards
Ted
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