INTERACTION OF ISOTROPIC TURBULENCE WITH SHOCK-WAVES - EFFECT OF SHOCK STRENGTH

As an extension of the authors' work on isotropic vortical turbulence interacting with a shock wave (Lee, Lele & Moin 1993), direct numerica l simulation and linear analysis are performed for stronger shock wave s to investigate the effects of the upstream shock-normal Mach number (Mi). A. shock-capturing scheme is developed to accurately simulate th e unsteady interaction of turbulence with shock waves. Turbulence kine tic energy is amplified across the shock wave, and this amplification tends to saturate beyond M-1 = 3.0. An existing controversy between ex periments and theoretical predictions on length scale change is thorou ghly investigated through the shock-capturing simulation: most turbule nce length scales decrease across the shock, while the dissipation len gth scale (<(rho)over bar>q(3)/epsilon) increases slightly for shock w aves with M-1 < 1.65. Fluctuations in thermodynamic variables behind t he shock wave are nearly isentropic for M-1 < 1.2, and deviate signifi cantly from isentropy for the stronger shock waves, due to the entropy fluctuation generated through the interaction.