  This paper develops the genuinely multidimensional HLL Riemann solver for the
two-dimensional special relativistic hydrodynamic equations on Cartesian meshes
and studies its physical-constraint preserving (PCP) property. Based on the
resulting HLL solver, the first- and high-order accurate PCP finite volume
schemes are proposed. In the high-order scheme, the WENO reconstruction, the
third-order accurate strong-stability-preserving time discretizations and the
PCP flux limiter are used. Several numerical results are given to demonstrate
the accuracy, performance and resolution of the shock waves etc. as well as the
genuinely multi-dimensional wave structures of our PCP finite volume schemes.
