High-order Moving Overset Grid Framework for Rotor Flows

Accurate resolution of complex wake structures in rotor flows presents significant computational challenges due to the wide range of spatial and temporal flow scales involved. Traditional rotor flow simulations often require artificial dissipation or spatial filtering to maintain numerical stability, which can non-physically dampen critical features such as tip vortices and rotor wake turbulence. This work presents a high-order, non-dissipative moving overset grid approach designed to address those concerns. The proposed method employs a sixth-order central difference scheme in the interior and a summation-by-parts (SBP) boundary treatment to achieve global fourth-order accuracy. Overset grid connectivity at interfaces is handled using a simultaneous approximation term (SAT) penalty method with characteristic decomposition, eliminating the need for artificial dissipation. The framework is implemented in a generalized curvilinear coordinate system and is applicable to moving flow problems where the overset grid follows a body in motion, making it well-suited for simulating flapping, pitching, or rotating components. Validation is conducted using a series of inviscid and viscous test cases, including convecting vortices over moving 2-D and 3-D overset grids, as well as pitching and heaving airfoils and wings. These benchmark results demonstrate the framework's long-time stability and accuracy in resolving small-scale features. The developed method is then applied to three-dimensional rotor flow simulations to capture wake dynamics and tip vortex evolution with high fidelity.