MHK_RM1_Fixed test running

Dear all,

I have tried running the MHK_RM1_Fixed turbine through a sweep of TSR at constant inflow of 2 m/s. Graph are shown below, and please ignore the different cases, these are just testing the impact of enabling ‘TwrPotent’ and ‘TwrAero’:

the simulation fails to properly simulate at lower TSRs and looks sensible for simulations after TSRs of around 4.5. When conducting a single simulation at the lower TSRs the logs noted that cavitation is occuring.

As a beginner user, may I ask what is happening at these lower TSRs?

Regards,
Ariff

Hello Ariff,

At low TSR’s the angle of attack increases, moving towards or past stall. In this region, the angle of attack is also more sensitive to small changes in the rotational speed. There is some instability in the drivetrain flexibility in this region for this reference design. Disabling the drivetrain flexibility (DrTrDOF in MHK_RM1_Fixed_ElastoDyn.dat) should give you more physically expected results for the full range of TSR’s. I suspect that the cavitation warning you are seeing is due to this unstable motion, and will go away without the drivetrain DOF.

Thanks,

Will