  In this paper, a third order gas kinetic scheme is developed on the three
dimensional hybrid unstructured meshes for the numerical simulation of
compressible inviscid and viscous flows. A third-order WENO reconstruction is
developed on the hybrid unstructured meshes, including tetrahedron, pyramid,
prism and hexahedron. A simple strategy is adopted for the selection of big
stencil and sub-stencils. Incorporate with the two-stage fourth-order temporal
discretization and lower-upper symmetric Gauss-Seidel methods, both explicit
and implicit high-order gas-kinetic schemes are developed. A variety of
numerical examples, from the subsonic to supersonic flows, are presented to
validate the accuracy and robustness for both inviscid and viscous flows.
