Mixed-element USM3D flow solver for NASA TetrUSS(LAR-19841-1)

The NASA Tetrahedral Unstructured Software System (TetrUSS) has served as a reliable computational aerodynamic analysis tool for Government and Industry for over 2 decades. TetrUSS has twice won the NASA Software of the Year Award in 1996 and 2004. The legacy Navier-Stokes flow solver within TetrUSS, USM3D, is based on fully tetrahedral cell-centered discretization. The present work extends the solver capability to handle mixed element grids composed of hexahedral, prismatic, pyramidal, and tetrahedral cells. Furthermore, additional algorithmic capabilities have been implemented that significantly improve its robustness and time to solution. These changes were so extensive that an entirely new code has been written.