Time Spectral Method for Rotorcraft Flow

This paper proposes a fast and efficient way to simulate time-periodic unsteady threedimensional rotorcraft flow for both Euler and Reynolds averaged Navier–Stokes equations. Based on the recently developed Time Spectral method, accurate results for hover and forward flight cases were achieved while gaining efficiency on the traditional dual time stepping scheme, and being simpler than the nonlinear frequency domain type solvers. Two new formulations for Vorticity Confinement for compressible flows were explored. The first formulation uses the local velocity magnitude to scale the confinement parameter and the second uses a helicity to determine the strength of the confinement term. The addition of the confinement term has no effect on the surface pressure distribution and negligible errors in the calculations of the coefficients of lift and drag.

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