Stitching and deformation of non-overlapping meshes for unsteady rotorcraft aerodynamics

A mesh manipulation technique is proposed to handle the changing computational domain for the unsteady numerical simulation of rotorcraft aerodynamics. The approach consists in having a large stationary mesh around the non-rotating part of the rotorcraft with dedicated non-intersecting rotary meshes around each rotor. These blocks of mesh are non-overlapping and separated by empty gap spaces which are stitched together with tetrahedral elements at each time step of the unsteady simulation. Additionally, the rotary meshes may be subject to deformation to accommodate rigid and elastic rotor blade motions, as well as potential ice accretion. The technique is shown to maintain the geometric quality of the mesh elements throughout a simulation, reducing the need for re-meshing due to mesh degradation. Additionally, as the mesh blocks are connected via stitching to form a single cohesive mesh at each time step, no interpolation is required between mesh domains promoting for time accurate simulations of helicopter aerodynamics.