Numerical Characterization of the Aeroacoustics of Tandem Propellers in Hover

This research focuses on the numerical analysis of aerodynamics and aeroacoustics of complex tandem propeller configurations for Vertical Take-Off and Landing vehicles. Results from solvers with different fidelity are compared. A reference high-fidelity solution is generated for an isolated rotor by solving the unsteady Reynolds-Averaged Navier-Stokes (uRANS) equations with SU2. On the other hand, a mid-fidelity solution is computed for both single and multiple propellers using the DUST solver, based on an integral boundary element formulation and a vortex particle method for wakes. Experimental measurements of integral loads, as well as, of the flow field are also presented for comparison. Good correlation with measurements is found for all the configurations. In addition, the study incorporates a numerical comparison of tonal noise propagation using the Ffowcs Williams–Hawkings (FWH) formulation coupled with both solvers. In specific tandem configurations an increase of the second blade passing frequency is found, due to the interaction between the propellers.