Numerical Simulations of Large-Scale Turbulence Ingestion in Forward Flight Propellers

Urban air mobility (UAM) vehicles are likely to encounter flow with high levels of turbulence,

arising from the atmospheric flow interacting with obstructions in an urban setting.

Therefore, understanding the effects of rotor-ingested turbulence on the aerodynamic noise

of propellers is crucial for the optimization of flight operations. The present study employs

numerical simulations to examine the aerodynamic and aeroacoustic performance of a propeller

ingesting wake turbulence induced by a circular cylinder, producing two-dimensional,

large-scale vortical structures which impinge upon the rotating propeller. The simulation

was conducted using Lattice-Boltzmann/Very-Large Eddy Simulation solver, PowerFLOW®,

coupled with FW-H acoustic analogy. The numerical approach has been validated in earlier

studies and the simulation agrees well with experimental results for both aerodynamic and

aeroacoustic characteristics. Flow field results reveal a significant rise in turbulence levels

near the blades, which indicate an elevated level of turbulence interaction noise. This corresponds

well with the significantincrease in broadband noise components when compared to

the isolated propeller, showing haystacking around the blade pass frequency.