The fragmentation of a drop of liquid (water, alcohol, glycerin) under the action of an air shock wave with a pressure of 0.2 and 3.2 atmg is studied experimentally and theoretically. The experiments are carried out using an air shock tube, and the liquid drop diameter is approximately 0.6 and 2 mm. The process is studied using high-speed video recording. Dispersed liquid particles from ≈5 μm in size are detected, liquid particle size distributions are plotted, and the particle velocities are determined. The experimental results are compared with the results of computational–theoretical estimation.

This paper presents the results of experimental and computational studies of instability development and mixing at the contact boundaries between gases of different densities. It has been shown that instability and mixing at two contact boundaries in a three-layer gas systems occur after a shock wave with a Mach number M = 1.3 that forms on the left end and moves along the tube has passed through the contact boundaries. Two experiments were performed, in the first of which the central layer was filled with a heavy gas (SF6 gas), and in the second experiment, it was filled with a light gas (helium). On the left and right of the central layer was air at atmospheric pressure. A comparison of the results was performed.

A laboratory experimental complex is presented, with which it is possible to study hydrodynamic instabilities and turbulent mixing with a micron spatial resolution and a nanosecond time resolution and then to process results with high precision. The arrangement of the complex and instrumentation is shown. The complex has been used to study turbulent mixing zones that develop under Rayleigh–Taylor and Kelvin–Helmholtz instabilities at gas–liquid interfaces and Richtmyer–Meshkov instabilities at an interface of gases. New results have been obtained: thin micro-cumulative liquid jets can be ejected from the turbulent mixing zone; after the passage of a shock wave through the zone of turbulent mixing of gases the zone tends to be homogeneous and the shock wave is distorted and expanded. The sizes of fluid particles in the zone of turbulent mixing of substances have also been determined.

This paper presents the results of an experimental study of particle ejection into low (0.05 atm) vacuum from a narrow (0.2–0.8 mm) rough ( Rz = 20–50 μm) surface of a lead sample subjected to a shock wave of intensity about 17 and 34 GPa. The ejecta was recorded with a video camera in the microscopic mode with short laser irradiation. Due to the small optical thickness of the ejecta, particle spectra at approximately 80% of the ejecta height measured from the front of the ejecta were obtained. It was found that when lead is in the solid state (17 GPa), jets consisting of a lot of particles are ejected from the rough surface; when the lead is in the liquid state (34 GPa), a lot of thin (from 7 μ m) microcumulative jets are ejected from the metal surface, and with time they break up into particles.

The experimental data and the results of direct numerical simulation of the flow developed in a constant-cross-section tube in passage of a shock wave through a three-layer gas system are presented. The three-layer systemis formed as a result ofmounting two thin films in the tube and filling the space between them with gases of different densities. The first interface (thin film) makes an angle of 45◦ with the shock front and the second interface is located in parallel to the front. The shock wave is formed at the left tube end and moves towards the first interface at the Mach number M = 2.4. The results of simulation of the problem are compared with the experimental data.

The interaction of a shock wave with turbulent flow was experimentally investigated. The case where a shock wave formed at one end of the tube, passed through the interface between two quiescent gases with different densities (air–CO2 or air–Ar), was reflected from the end of the tube, and interacted with the zone of turbulent mixing formed at the interface. The Mach number of the shock wave incident on the interface in air was M ≈ 2.37–2.57. The flow field was recorded using the schlieren method and high-speed video recording. It was found that after passing the mixing zone, the shock-wave front was deformed and became unstable.

In view of the possible effect of contamination of a plasma by metal particles on the operation of a number of facilities or on the detection of the motion of liners by Doppler methods, a particular attention has been recently focused on the problem of the ejection of particles from the shock-loaded free surface of a sample or on the “dusting” problem. Most information concerns the dusting source associated with the roughness of the surface, manufacturing technology, and the defectiveness and aging of a material. Factors affecting this process such as the profile and amplitude of the pressure on the front of the shock wave arriving at the free surface of the sample, the presence of the gas in front of the free surface, and the pressure in this gas are less studied.

This work presents the results of experimental and numerical studies on the process of turbulent mixing ocurring at the contact boundaries of three-layer gas systems during the passage of a stationary shock wave with a Mach number M ≈ 1.3. The experiments are carried out in an air shock tube. The working gases are air, SF6, and He. The flow structure is recorded by a schlieren method with laser illumination. The data on the nature of turbulent mixing in two-dimensional flows are obtained.

The results of the experimental study of the Reynolds number effect on the process of the Rayleigh-Taylor (R-T) instability transition into the turbulent stage are presented. The experimental liquid layer was accelerated by compressed gas. Solid particles were scattered on the layer free surface to specify the initial perturbations in some experiments. The process was recorded with the use of a high-speed motion picture camera. The following results were obtained in experiments: (1) Long-wave perturbation is developed at the interface at the Reynolds numbers Re < 10(4). If such perturbation growth is limited by a hard wall, the jet directed in gas is developed. If there is no such limitation, this perturbation is resolved into the short-wave ones with time, and their growth results in gas-liquid mixing. (2) Short-wave perturbations specified at the interface significantly reduce the Reynolds number Re for instability to pass into the turbulent mixing stage.

In this paper, we present the results of our experiments on the study of the dispersion of a liquid drop (Ø=2 mm, tributyl phosphate) under the influence of an air shock wave (SW) with an intensity of 0.2–42 atm. The experiments were performed using an air shock tube. The SW was created by exploding a C2H2+2.5O2 mixture, compressed air or compressed helium. Recording of the dispersion process was performed by using high-speed macro- and microfilming (the Schlieren method and traditional filming). Macrofilming allowed us to register an integral picture of the process of drop dispersion and to determine the time of drop evaporation. Microfilming allowed us to resolve fragments of the liquid with sizes ⩾2 μm and to obtain the distribution of the spectrum of drop fragments, which is necessary for calibrating the analytical models.

In this paper, we present the results of our experimental study of the development of turbulent mixing (TM) occurring at a Rayleigh–Taylor instability at the liquid–gas interface with mixing zone width (H) up to 200 mm. A liquid layer (water) of mass up to 3.3 kg was accelerated in a transparent cylindrical channel of Ø=210 mm with the help of compressed air. The pressure of compressed air reached 8.4 atm, acceleration rate g=(0.5–1)×103g0 (where g0=9.8 m s−2), layer displacement S was up to 350 mm, penetration depth of the gas front into the liquid hLH was up to 50 mm and the Reynolds number of the flow reached (where A≈1 is the Atwood number and ν is the coefficient of kinematic water viscosity). The following results were obtained: (i) the coefficient βLH, which characterizes the average penetration rate of the gas front into the liquid (βLH=ΔhLH/Δ2S), was βLH≈0.11 over the range of layer displacements 10 mm<S<50 mm (at Re up to 2×105); (ii) the coefficient βLH decreased by approximately 35% with increasing displacement of the liquid layer from ≈50 mm to ≈100 mm (with an increase of Re from 2×105 to 5×105); then, with a further increase of layer displacement up to 350 mm (with an increase of Re until ≈5×106), βLH did not vary and remained βLH=0.06–0.08; in this case, some pulsation of the penetration of the gas front into the liquid was observed; (iii) separate large bubbles of the TM zone became unstable with the onset of time—secondary bubbles formed on them.

The results of our experimental investigation of the turbulent mixing occurring at a Richtmayer-Meshkov instability driven by a shock wave (SW) in gases at different Mach numbers (M) ranging from approximate to 1.4 to approximate to 9 are presented in this paper. The experiments were performed by using an air shock tube with a channel section of 40 x 40 mm(2). The SW passed from 'light' to 'heavy' gases. Air (helium) was used as a 'light' gas and Xe, CO2 and Ar were used as 'heavy' gases. The gases were initially separated by a thin (approximate to 1 mu m) polymer film, which was failed after the passing of the SW. A film of the flow was made using a high-speed camera by the Schlieren method.

The experimental technique for investigation of turbulent mixing is presented in this report. Turbulent mixing (TM) arises at Richtmayer-Meshkov instability at the interface gas-gas accelerated by a shock wave. Helium (He) and air (Air) was used as light gas, as heavy gas - sixfluorine sulfur (SF6). In all the experiments a shock wave propagated from light gas to heavy gas. Mach number of a shock wave in SF6 has changed from 2 to 9. The flow was recorded by the use of shlieren method during rapid motion-picture recording.

We present the results of the experimental study of viscosity effect on turbulent mixing development (TM) occurring at Raylegh-Taylor instability at the boundary of a liquid layer accelerated by compressed gas. In the experiments dynamic viscosity of liquid has varied from mu=1 cP to mu=1,480 cP. As liquid we used: water, glycerol, aqueous solution of glycerol having known viscosity. The value of acceleration of a liquid layer has amounted to: g congruent to 10(3) g(0) and g congruent to 10(5) g(0). As gas we used helium compressed previously up to pressure 4.5-500 atm. It has been demonstrated that when changing liquid viscosity a mixing zone structure changes. This influences on a mixing character of substances.