Dear Dr. Jason.
A heading of 0 of the WaveDir and PropagationDir corresponds to wave and wind propagation in the positive X-axis direction,
when I changed the PropagationDir to 180, it seems the attack angel is two high and the mach number is over 1, then the simulation aborted.
So I want to know how to make the wind propagation in the negative X-axis direction, in which condition the blade or the wind turbine propagation in the positive X-axis direction.
Thanks for your help.
Best Regards
Dear Yuanzhao,
I’m sorry, but I’m not sure I understand your question. If the wind propagates along the negative X-direction, you will have a nacelle-yaw error of 180 degrees (hence the large angle of attack), unless you’ve yawed the wind turbine by 180 degrees.
What condition are you trying to simulate?
Best regards,
Dear Dr. Jason,
I’m sorry I didn’t make it clear, in test25 of OC4, since the angle between adjacent Line is 120°,the original condition is inline, that is the wind and wave propagation are 0°.
I want to simulate the ‘between line’ conditon, that is the wind and wave propagation are 180°.
It is the same as what you say that I want to yaw the wind turbine by 180 degrees, so I don’t know how to yaw the wind turbine by 180 degrees.
Thanks for your help,
Best Regards,
Dear Yuanzhao,
Yes, if you set the wind propagation to 180 degrees in InflowWind (PropagationDir = 180), you’ll likely want to set the nacelle-yaw angle to 180 degrees to avoid having a large yaw error. To set the nacelle-yaw angle, if the nacelle-yaw DOF is disabled in ElastoDyn (YawDOF = False), all you have to do is set the initial nacelle-yaw angle in ElastoDyn to 180 degrees (NacYaw = 180). If the nacelle-yaw DOF is enabled in ElastoDyn (YawDOF = True), you’ll also have to set the neutral yaw angle in ServoDyn to 180 degrees (YawNeut = 180) and set appropriate yaw spring and damper values in ServoDyn (YawSpr and YawDamp) to keep the nacelle at this angle.
Best regards,