MORE INVARIANT PROPERTIES OF SPURIOUS WAVES IN NUMERICAL COMPUTATIONS

It is shown that some of the properties of spurious waves that occur in computational fluid dynamics calculations (in particular in the inviscid case, when time stepping is conservative) are largely independent of how numerical time stepping is implemented. They depend primarily on the manner in which the spatial part of the equations is approximated. The properties that are shown to be invariant are the location of the turning points of the rays followed by sinusoidal components of those spurious waves, and, when they are generated by initial data, the asymptotic distribution of their energy.