Fractional Inflow Dynamics

摘要

Simplified inflow models play an important role in simulation, control and preliminary design of rotorcraft and wind turbines. This work shows how classical actuator disk vortex theory can be (1) extended into the time-domain, (2) used to analyze multi-rotor systems and (3) computed efficiently with the Fast Fourier Transform. The fractional Laplacian and spatial Fourier-analysis serve as the enabling theoretical tools. The basic theory is presented and previous analytical results are recovered as special cases. Measurement data from a wind turbine is used to validate the transient performance. Finally, a simple multi-rotor example is illustrated.