Hello,
I’m using OpenFAST v2.3.0.
I’m having a couple of issues with AeroDyn. I have designed a turbine model around the 15MW reference turbine. I have tuned a controller and I’m running fully aero-elastic simulations in OpenFAST. Each of my simulations are an hour long, there are 22 in total (4-26m/s, 5.5% turbulence at v=15 m/s)
Depending on my exact setup, sometimes I get failures on a few of the higher wind-speed simulations, I think due to convergence of AeroDyn. Normally the error messages OpenFAST gives are super helpful, however this one was less so - I have attached the error (error.png). The simulations are stable up until this point with no apparent misbehaviour of the controller.
I read on some of the other posts that people have had issues running AeroDyn when they end up with a negative horizontal local velocity. In the same posts, it was hypothesised that changing the tower potential flow correction between 1,2 can improve things and also increasing the time-step.
What is odd to me is that the error only occurs at node 1 the first blade - I have attached the blade node definition (AeroDynBladeNode.png), the airfoil reference is too a cylindrical section. Given that the solutions are stable otherwise, I think it’s highly unlikely that the fore-aft motion is sufficiently high to cause a negative velocity (it would have to be approximately 20 m/s in magnitude at the tower top).
Any thoughts would be greatly appreciated 
Best,
Sam
