A k-ε model for turbulent mixing in shock-tube flows induced by Rayleigh–Taylor instability

Abstract

A k‐ε model for turbulent mixing induced by Rayleigh–Taylor instability is described. The classical linear closure relations are supplemented with algebraic relations in order to be valid under strong gradients. Calibrations were made against two shock‐tube experiments (Andronov et al. [Sov. Phys. JETP 4 4, 424 (1976); Sov. Phys. Dokl. 2 7, 393 (1982)] and Houas et al. [Proceedings of the 15th International Symposium on Shock Waves and Shock Tubes (Stanford U.P., Stanford, CA, 1986)]) using the same set of constants. The new interpretation of the experimental data of Brouillette and Sturtevant [Physica D 3 7, 248 (1989)], where the mixing length is discriminated from the wall jet, requires a different numerical value for the Rayleigh–Taylor source term coefficient. A detailed physical study is given in both cases. It turns out that the spectrum is narrower in the Brouillette and Sturtevant case than in the Andronov et al. case but the small length scales are of the same magnitude.