THE use of detonations as ignition mechanisms in scramjet designs goes as far back as 1946. 1 Subsequent work on the subject finally led to the use of oblique detonation waves as the most effective design of detonative ramjets. 2'4 However, the experimental evidence for stable, oblique detonation waves (ODW) is sketchy. 5'10 To remedy this situation, an experiment is being designed to verify the existence of a standing detonation on a wedge and prove the validity of the ODW engine concept. 11 There is also a need for accurate numerical simulations of the reacting flowfield, both the design purposes and for analysis. To this effect, a new code is being developed, based on an explicit, second-order total variation diminishing (TVD) scheme. 12'17 Viscous, diffusive, and chemical processes are added to the scheme by an operator-splitting method. The overall scheme is second-order accurate in space and first-order accurate in time.(Individual processes, such as convection and chemical kinetics, are second-order accurate in time, but the coupling reduces the overall time accuracy to the first order.) The code has a multigridding capability, where grids are patched along their common boundaries. The patching process is exactly flux conservative. The code has been applied to the numerical simulations of a generic strut configuration, where fuel (H2) is injected and mixed with air. Downstream of the injector is a wedge that will support a detonation wave. The overall flowfield occupies several grids. The downstream boundary conditions at each