Hello everyone!
I’m a newcomer who has just joined this community. I’m encountering such a problem.
I’m trying to integrate wave energy devices with Spar-type platforms, and I’m using the OC3 Hywind+5 MW baseline turbine model. While the standalone Spar platform with wind turbine functions properly, I keep getting a FAST error when integrated the WEC system. Specifically, when wind speed exceeds 7 m/s or rotor speed surpasses approximately 11 RPM, FAST throws an error stating: “High VNB velocity encountered during induction factor calculation”, and then stop the simulation.
Could anyone help me understand what might be causing this instability? Any insights or suggestions for parameter adjustments or modeling considerations would be greatly appreciated!
Dear @Renjie.Gao,
Can you clarify how you are modeling the wave-energy converter (WEC) system into FAST / OpenFAST?
Best regards,
Dear Jason, thank you for your response.
I’m trying to integrated the aero-servo-elastic calculation module of FAST with the hydrodynamic analysis module of AQWA by employing the F2A (FAST to AQWA) coupled analysis tool. The integration was further enhanced by incorporating a multi-body dynamic model of three articulated pendulum-arm type WECs. But, as I mentioned before, when wind speed exceeds 7 m/s or rotor speed surpasses approximately 11 RPM, it goes wrong. 
Best regards,
Dear @Renjie.Gao,
I’m vaguely familiar with F2A (FAST to AQWA coupling), but this interface was not developed or used by NREL, so, I’m not the best one to answer questions on it.
Best regards,
Okay, that’s okay. Thank you all the same!