Characteristic boundary conditions and its application to resonance tube

摘要

To investigate the pressure pulsation in a resonance tube, a computer program based on the unsteady compressible Euler equations has been developed. The convective terms are constructed using a Roe's approximate Riemann solver and MUSCL for high accuracy is employed. To limit oscillations near shocks, Koren's differentiable limiter is adopted and an explicit two-step Runge-Kutta method is used for time integration. Several characteristic boundary conditions suggested by Thompson, Watson-Myers and Hwang were tested and discussed to understand their physical meanings. Through the above tests, appropriate boundary conditions are selected and applied to simulate the pressure pulsation in the resonance tube. The calculation results are compared with the experiment by Merkli and Thomann. The computed amplitude and the period of pressure pulsation showed good agreement with experiment except peaks. It is believed that the practical engineering problems concering acoustics can be directly simulated using Euler equations.