Wavelet-Based Vorticity Transport Technology for Rotorcraft Flowfield Analysis

A hybrid Eulerian vorticity transport/Navier-Stokes methodology is proposed for the accurate prediction of unsteady rotorcraft vortical flow features with particular attention to the efficient transport of rotor wake vorticity to the farfield with minimal dissipation. High-fidelity Navier-Stokes modeling will be used for the capturing of near-body flow features, while a novel, first principles, wavelet-based multiresolution Eulerian vorticity transport model will be developed for use in the near-field, vortex-dominated region and for convecting the shed vorticity into and through the far-field region. These two flow regions will be interfaced in a unique fashion in order to capture propagation of the vorticity, entropy and acoustic waves without unphysical reflections. Wavelet technology is expected to provide an order of magnitude reduction in grid and CPU requirements. In Phase I, the wavelet-based multiresolution Eulerian vorticity transport model will be developed as a stand-alone module, while an efficient interface will be developed between the vorticity transport model and Navier-Stokes code. The feasibility of the proposed technology will be demonstrated by the prediction of three-dimensional vortex shedding relevant to Blade Vortex Interaction (BVI). In Phase II, the vorticity transport and hybrid interface modules will be generalized and integrated into modern and well-used high-fidelity rotor CFD codes and verified and validated on a range of rotorcraft datasets.