The design, operation, and functionality of the multifunctional shock tube (MST) facility at the Russian Federal Nuclear Center–VNIITF are described. When complete, the versatile MST consists of three different driver sections that permit the execution of three different classes of experiments on the compressible turbulent mixing of gases induced by the (1) Richtmyer–Meshkov instability (generated by a stationary shock wave with shock Mach numbers <5), (2) Rayleigh–Taylor instability (generated by compression wave such that acceleration of the interface is <105g0, whereg0= 9.8 m/s2), and (3) combined Richtmyer–Meshkov and Rayleigh–Taylor instability (generated by a nonstationary shock wave with initial pressure at the front 5 × 106Pa and acceleration of ≤106g0of the interface). For each of these types of experiments, the density ratio of the gases is ρ2/ρ1≤ 34. Perturbations are imposed on a thin membrane, embedded in a thin wire array of microconductors that is destroyed by an electric current. In addition, various limitations of experimental techniques used in the study of interfacial instability generated turbulent mixing are also briefly discussed.

Experiments conducted on the EKAP facility at the Russian Federal Nuclear Center-VNIITF concerning the stabilization of Rayleigh-Taylor instability-induced mixing in miscible liquids by the formation of a molecular diffusion~or transitional! layer between the liquids initially were described. The experiments had an Atwood number of 103. The acceleration was 3500 times that of Earth's gravity, and several values of diffusion layer thickness were considered. The experiments showed that the growth of the turbulent mixing zone could be delayed by adjusting the amplitude of the initial perturbations and the characteristic thickness of the diffusion layer. This has been observed in experiments conducted with water and mercury. The mixing layer evolution was imaged using X-ray radiography.

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An experimental investigation into inertial properties of the developed Rayleigh-Taylor instability with the different initial values of the kinetic energy of turbulence has been performed. The experiments were performed by using two fluids having different densities with density ration n = 3. Fluids were placed in an ampoule. At the unstable stage of motion, the ampoule was moving under an acceleration. At a certain instant of time the acceleration was removed and the ampoule moved under the force of inertia. By means of pulsed X-ray photography, the mixing region size and the time-space distribution of the average density of matter in the turbulent mixing region have been determined at different instants of time. The time-space distributions are compared with those obtained by semiempirical theories of mixing.