Numerical studies of wind turbine acoustics

The use of an unsteady CFD simulation to provide data for a full acoustic analysis of a wind turbine has been demonstrated. The OVERFLOW solver was employed to predict the nearfield conditions. The data from the CFD simulation was sampled to provide the input for the PSU-WOPWOP Ffowcs Williams-Hawkings solver. PSU-WOPWOP was employed to predict the farfield acoustic conditions at locations that correspond to a virtual phased array of microphones. The pressure "measurements" from the virtual array were then processed using the Beamform Interactive software package using the same techniques employed for physical microphone array measurements. All the stages of this process have now been demonstrated, and the process is able to predict the expected broadband noise sources focused near the rotor tips. When fully realized, this technology offers the possibility of screening wind turbine designs for acoustical qualities prior to building and operational testing.