Wavelet-Based Vorticity Transport Technology for Rotorcraft Flowfield Analysis

Improved understanding of rotorcraft aerodynamics through numerical simulations requires accurate modeling approaches viable for large-scale computations. Conventional Navier-Stokes and Lagrangian methods have severe limitations in effectively dealing with the complexity and length-scales involved. The proposed research focuses on zonal first principal-based methods for capturing strong rotor tip vortex formation, interactions with rotorcraft blades/body, and vortex convection in distant farfield with high resolution. In this research, an innovative wavelet-based adaptive mesh Eulerian vorticity transport model for vortical wake will be combined with an existing rotorcraft Navier-Stokes model for immersed near-body regions of the rotorcraft, using an appropriate overset technology for dynamic grid interfacing. Feasibility of this wavelet method for Eulerian vorticity transport was demonstrated in Phase I. Research efforts in Phase II will focus on strengthening the unique merits and practical applicability of the methodology. The vorticity transport model will be constructed on an adaptive Cartesian mesh infrastructure with accurate flux and velocity computation schemes to efficiently conserve vortex strength and structure. The wavelet-based multiresolution algorithm, ideally suitable for the data structures will be superimposed on the vorticity model with much increased functionality of mesh adaptation. A space-filling curve method will be utilized to enable massive parallelization for large-scale simulations and analysis of unsteady rotor wake. The developed rotorcraft computational tools will be validated and demonstrated on benchmark rotorcraft problems.