A Comparison of the Lax-Wendroff Technique and the Method of Characteristics for Engine Gas Dynamic Calculations Using Fast Fourier Transform Spectral Analysis

A direct comparison between the mesh-method of characteristics (MOC) and the two-step Lax-Wendroff method with flux corrected transport (LW2+FCT) is presented in terms of calculated pressure, velocity and emitted noise, in the time and the frequency domain, by means of fast Fourier transform analysis. Inspection of sound pressure levels derived from pressure/crankangle data reveals that the results from the Lax-Wendroff method contain larger contributions due to high frequency components than the results from the method of characteristics; this will influence the accuracy of noise predictions made with the two techniques.