Numerical Studies of Wave Propagation Phenomena in Shock and Expansion Tubes

The results from numerical simulations of one-dimensional in viscid and two-dimensional axisymmetric viscous simulations in shock and expansion tubes are presented. A code using the HLLC approximate Riemann solver developed by Toro et al [43] was used to carry out the simulations. The ability of the code to provide accurate solutions for one-dimensional Euler equations has been verified by examining Sod's ideal shock tube problem and the details in shock wave and contact surface were investigated. It shows that the details were accurate as the initial pressure ratio across a primary diaphragm was low. For high initial pressure ratio across the primary diaphragm, the numerical simulations of the simple shock tube problem were carried out. It shows that there is an initial overestimation in shock speed. The computed heat transfer rate compared to Mirels' theory and the duration of the test time were investigated. The tailoring interface technique used widely in shock tube researches was considered because of the possibility to increase the test time. The simulations for inviscid flow with tailored, under-tailored and over-tailored conditions were carried out and the results are given here. Some simulations for viscous flow were also carried out and there was a pressure loss in the driver chamber due to heat transfer. The acoustic transverse wave propagation phenomenon caused by the interaction between heat transfer and pressure loss was investigated. The simulations of expansion tube with two different pressure ratios across the secondary diaphragm were carried out. The details of wave propagation of the primary shock interaction with the secondary diaphragm and the interaction between the reflected shock and the secondary expansion were investigated. The durations of the test gas with good quality were also discussed here.