  Non-classical non-linear waves exist in dense gases for large specific heats
at pressures and temperatures of the order of critical point values. These
waves behave precisely opposite to the classical non-linear waves, with
inverted classical waves like the expansion shocks which do not violate entropy
conditions. More complex equation of state (EOS) other than the ideal or
perfect EOS is typically used in describing dense gases. Algorithm development
with non-ideal/real gas EOS and application to dense gasses is gaining
importance from a numerical perspective. Extending the algorithms designed for
perfect gas EOS to dense gas flows with arbitrary real gas EOS is non-trivial.
Most of the algorithms designed for prefect gas EOS are modified significantly
when applied to real gas EOS. These algorithms can become complicated and some
times impossible based on the EOS under consideration. The objective of the
present work is to develop central solvers with smart diffusion capabilities
independent of the eigenstructure and extendable to any arbitrary EOS. Euler
equations with van der Waals EOS along with two newly developed algorithms,
Method of Optimal Viscosity for Enhanced resolution of shocks (MOVERS+) and
Riemann Invariants based Contact capturing Algorithm (RICCA), are used to
simulate dense gasses over simple geometries. Various One Dimensional (1D) and
Two Dimensional (2D) benchmark test cases are validated using these algorithms,
and the results are compared with the those obtained from the literature.
