For flows with strong periodic content, time-spectral methods can be used to obtain time-accurate solutions at substantially reduced cost compared to traditional time-implicit methods which operate directly in the time domain. The time-spectral approach requires the simultaneous coupled solution of multiple time instances, which can be performed effectively in parallel on modern multicore parallel computer architectures. Although time-spectral methods are only applicable to purely periodic flows, in previous work we have demonstrated the ability of a hybrid BDF/time-spectral approach for simulating quasi-periodic flows with good overall efficiency. A quasi periodic flow is defined as one which involves a slow transient in addition to a higher frequency periodic component. In this paper, we apply the BDF/time-spectral approach to compute the important practical problem of time dependent helicopter maneuver loads, which combine the periodic rotor motion with a slower vehicle maneuvering transient. The simulation includes a rotating and deforming mesh with prescribed aeroelastic blade deflections. The formulated BDF/time-spectral approach is compliant with the geometric conservation law, and produces equivalent temporal accuracy using less computation effort compared to a traditional BDF time-implicit approach.
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