A Parallel, Object-Oriented Framework For Unsteady Free-Wake Analysis Of Multi-Rotor/Wing Systems

The development, validation, and applications of an object-oriented free-wake solver for multi-rotor and fixed-wing systems are outlined here. Advantages of utilizing the object-oriented philosophy for modeling the multi-rotor/wing free-wake problem are described. To explore the feasibility of utilizing conventional desktop workstations, the vortex lattice methodology's time complexity is examined as an evolving n-body problem and the advantage gained from employing wake roll up models is demonstrated. Modifications in typical formulae to leverage features of multi-core systems and improvements in computational performance obtained from these modifications are illustrated using a roofline analysis. The free-wake solver incorporating these optimizations is then employed-after extensive validation-to simulate a distributed propulsion aircraft and a multi-rotor urban mobility vehicle. The paper also proposes a novel lattice skew parameter for monitoring instabilities in wake solutions commonly observed in rotorcraft free-wake analysis. (C) 2020 Elsevier Ltd. All rights reserved.