Comparison of unsteady flow calculations in a pipe by the method of characteristics and the two-step differential Lax-Wendroff method

This paper introduces a comparison of two of the methods which are most frequently used, at present, for the solution of an unsteady flow in the pipe system of internal combustion engines. These are (i) the method of characteristics and (ii) the two-step differential Lax-Wendroff method. In the case of homentropic flow a comparison is made between the lattice-point and mesh method of characteristics, and the two-step differential method is shown. In the case of non-homentropic flow the mesh method and two-step differential methods are also compared. The results show that for non-homentropic flow the two-step Lax-Wendroff method is faster and for engineering applications it is easier to implement on the computer.