[American Institute of Aeronautics and Astronautics 14th AIAA/CEAS Aeroacoustics Conference (29th AIAA Aeroacoustics Conference) - Vancouver, British Columbia, Canada ()] 14th AIAA/CEAS Aeroacoustics Conference (29th AIAA Aeroacoustics Conference) - On the Performance of the Quadrature-Free Discontinuous Galerkin Method on Hexahedral and Tetrahedral Grids for Linearized Euler Equations