A NUMERICAL STUDY OF NONLINEAR PROPAGATION OF DISTURBANCES IN TWO-DIMENSIONS

In the spirit of the method of characteristics, we present in this paper a generalized Taylor-Galerkin finite element model to simulate the nonlinear propagation of finite-amplitude disturbances. In a nonlinear Euler system, the multi-dimensional formulation is constructed through the conservation variables. Noticeable is that the scheme is found to exhibit high-phase-accuracy, together with minimal numerical damping. This scheme, therefore, is best-suited to simulation of disturbances in an acoustic field. To begin with, we validate the characteristic model by simulating two transport problems amenable to analytic solutions. Motivated by the apparent success, we apply the proposed third-order accurate upwind model to investigate a truly nonlinear acoustic field. The present analysis is intended to elucidate to what extent the nondissipative, nondispersive and isotropic characteristics pertaining to three wave modes of the acoustic system are still valid.