Artificial Selective Damping

The short waves are numerical contaminants of a computed solution. To improve the quality of a numerical solution, it is imperative that the short waves be automatically removed from the computation as soon as they are generated. A way to remove short waves is to add artificial selective damping terms to the finite difference equations.


Figure 7.1. Pressure waveform initiated by boxcar initial condition at 2000 time steps.


For this method to be acceptable, the damping terms must selectively damp out the short waves and have minimal effect on the long waves.