Implementation of a nonlinear filter with a Lagrangian formulation for the treatment of very high pressure reflected shocks (Q1891063)

The Engquist filter is implemented within the one-dimensional Lagrangian gas dynamics code HAROLD. The conservation version and the total variation diminishing version of the filter are combined with filtering performed in characteristics space. The present results show that the filter performs well in the Lagrangian system for very strong shocks. A new treatment of the wall boundary reflection for strong shocks that takes advantage of the filter is presented. Reflected shocks calculated using this technique show essentially no overshoots typical of classical finite-difference codes.