Rzero must be smaller than 1

Wind & Water Computer-Aided Engineering Software Tools
1

Hello,
I am getting a FAST error when I try to add a platform to my turbine model that says “Value of Rzero = 1.0001 must be smaller than 1”. I see that there have been some posts about this topic where some possible solutions include 1) increasing DR of the outermost element (when excessive blade stretching is not part of the problem… I am also not getting any “small angle assumptions” errors). This is the case for me and I have modified my blade outer DR (as well as other blade nodes) so that my Rzero = 1.0001 but will not go below 1. I have also modified initial conditions to try to alleviate this problem with no success. Please keep in mind that this only happens when I add a Platform file. Is there anything else that I can try to lower my Rzero value? Has any further work been done on this topic?

Thanks,
Colin

2

Dear Colin,

The RZero error is discussed in the forum topic found here: FAST throws: Rzero must be < 1 (particularly my post dated May 25, 2011). I don’t think I can provide any more advice other than what is already stated there. And there hasn’t been any progress on the AeroDyn development that will alleviate this error. My guess is there is some problem with your model that is making it go unstable, leading to excessive blade deflection that results in the RZero error.

Best regards,