Spontaneous emission of acoustic waves from shock fronts Free

The criterion for spontaneous emission of acoustic waves from shock fronts, , was obtained by D'yakov et al. [Zh. Eksp. Teor. Fiz. 27, 288 (1954); V. M. Kontorovich, ibid. 33, 1525 (1957); G. R. Fowles, Phys. Fluids 24, 220 (1981)]. Based on the previous work of the interaction of acoustic waves with a shock front [F. Xu, Acta Mech. Sinica (English edition) 3, 113 (1987)], a new criterion is obtained in this paper: C₀ > ω/k_y < C₁. Then, the causes for the discrepancy between these two criteria are discussed and some comments on the previous papers are made. In addition, the amplification of the shock front is investigated and the results are compared with those of previous works [G. R. Fowles, Phys. Fluids 24, 220 (1981); P. Harris, Tech. Rep. ARLCD‐TR‐78041 (1978)].