Wake encounters between two full-configuration UAM aircraft in forward flight: Aerodynamic response and implications for operational spacing

초록

Wake encounters between urban air mobility (UAM) aircraft can alter the aerodynamic response of following aircraft because multirotor wakes are highly unsteady and may interact with both rotors and fuselage. However, the effects of downstream wake evolution on the aerodynamic response during wake encounters between two full-configuration UAM aircraft remain poorly understood. Thus, this study examines wake encounter effects between two full-configuration UAM aircraft in forward flight using the in-house vortex-based aerodynamic solver VALOR, which couples the nonlinear vortex lattice method for rotor aerodynamics, the source-doublet panel method for airframe aerodynamics, and the vortex particle method for wake convection. The wake generated by the leading aircraft convects downstream and impinges on the following aircraft, producing position-dependent variations in aerodynamic performance. Six cases are considered at a fixed streamwise separation of x/R = 6 by combining advance ratios of mu = 0.15 and 0.23 with vertical separations of z/R = 0, -1, and -2. Results show that the advance ratio influences the wake convection path and thereby the relative encounter location between the wake and following aircraft. At mu = 0.15, the mean thrust reductions are 29.12%, 25.17%, and 11.10%, whereas the corresponding reductions at mu =0.23 are 25.63%, 14.17%, and 7.70%. The maximum mean torque reduction is 8.02%. Additionally, the fuselage pressure distribution and pitching moment vary with the position of the wake relative to the following aircraft, suggesting that wake effects extend beyond the rotor disks. These findings demonstrate that the aerodynamic response of following UAM aircraft during wake encounters must be assessed by considering both the wake convection path and wake position relative to the following aircraft.

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