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 SOM facility at the Russian Federal Nuclear Center-VNIITF, concerning the turbulent mixing induced by the Rayleigh-Taylor instability in a three-layer system of immiscible liquids are described. The fluids are contained in a small tank 6.4 cm ϫ 5.4 cm ϫ 12 cm, which is accelerated vertically downward by a gas gun. The mixing layer evolution was imaged by seeding one of the fluids with particles and using a bidirectional light sheet method~refractive index matching was used to minimize measurement errors!. Experiments were performed for two different accelerations~g ϭ 350 g 0 and g ϭ 100 g 0 , where g 0 ϭ 980 cm0s 2 , and the acceleration decreases with distance traveled!, and with aqueous solutions of glycerin and benzene~with density ratio 1.6!. The lower, middle, and upper layers were a sodium hyposulfite-glycerin solution, a water-glycerin solution, and benzene, respectively. The glycerin solution was seeded with particles. The principal objective of the experiments was to obtain the distribution of fluid particle sizes arising from the mixing of the immiscible fluids.

An experimental investigation into the asymptotic stage of the separation of the turbulized mixtures of two fluids with densities ratio n = 3 has been carried out. The turbulized mixtures resulted from Rayleigh-Taylor instability when the contact boundary between two fluids was moved under an acceleration. At a certain instant of time, the system changes from the gravitationally unstable mode to the gravitationally stable one by the way of changing of the acceleration sign. During the ampoule motion with the investigated fluids at the gravitationally stable mode, the depth of penetration of the heavy fluid into the light one was registered with the photographic method. The length of the ampoule way at the gravitationally stable mode has been fixed so that the final (asymptotic) stage of the separation could be registered. At the result of the measurements, it has been determined the separation process at the asymptotic stage has the same dimensionless velocity as at the initial stage.

Experiments with two pairs of gases with different densities with the initial values of the Atwood number A = 0.21 and 0.83 are performed in a multifunctional shock tube. Statistical and spectral characteristics of the mixing zone formed owing to the Richtmyer-Meshkov and Rayleigh-Taylor instability are obtained by the laser sheet technique, and the range of lengths of the main waves in the structure of this zone is determined. Introduction.A large number of models of turbulent mixing caused by the Richtmyer-Meshkov and Rayleigh-Taylor instability have been developed. In addition to k-ε models, they include models of the second and higher levels of closure [1, 2], whose verification and calibration cannot be performed with the use of integral characteristics of mixing (dimensionless mixing velocity and distributions of the mean density of the substance) obtained in laboratory experiments and require experimentally measured spectral characteristics of time-dependent density and velocity in the mixing zone.Statistical and spectral characteristics of the turbulent mixing zone formed under the consecutive actions of the Richtmyer-Meshkov and Rayleigh-Taylor instability were obtained for some time instants in the present work by the laser sheet technique [3] in a multifunctional shock tube (MST) at the Institute of Technical Physics [4]. The spectral characteristics are used to estimate the range of lengths of the main waves in the mixing zone.The structure of the mixing zone of gases with different densities was studied by the laser sheet technique in [5]. The distribution of density of the heavy gas in the laser sheet plane was obtained. A jump in density was found at the boundary between the heavy gas and the mixing zone. This fact contradicted the integral measurements of the density distributions of fluids with different densities, which were performed in [6] by the x-ray technique. Careful calibration of the measurement technique was performed in the present work.1. Arrangement of Experiments. The experiments were performed in a vertical MST with a square inner cross section 138 × 138 mm; the diagram of the shock tube is shown in Fig. 1. The upper part of the MST contains a section filled with an explosive gas mixture, which is a stoichiometric mixture H 2 + 0.5O 2 . This section is separated from the ambient atmosphere and from the remaining part of the MST by membranes 1 and 4 made of a Mylar film 20 μm thick. The membranes are located on grids consisting of thin metallic strings 0.1 mm in diameter; the cell size of the grids is 12 × 12 mm. The heavy and light gases are separated from each other by a membrane 6 made of a nitrocellulose film whose thickness is approximately 1 μm. The membrane is located on a grid composed of thin strong strings with a cell size of 6 × 6 mm. The MST sections are filled with gases having a pressure of 10 5 Pa and a temperature of 293 K. In the first series of experiments, the heavy gas was carbon dioxide (CO 2 ) with a density ρ 2 = 1.98 · 10 −3 g/cm 3 , and the light gas was hel...

Показано, что для объяснения экспериментальных результатов по дифракции микрочастиц не требуется использовать концепцию волн де Бройля. Эти результаты описываются на основе соотношения неопределенностей Гейзенберга. В качестве примеров рассматриваются известные результаты экспериментов Дэвиссона и Джермера по дифракции электронов и Резерфорда по рассеянию -частиц. Ключевые слова: Соотношение неопределенностей Гейзенберга, эксперименты Дэвиссона и Джермера, дифракция электронов, рассеяние альфа-частиц. Введение Согласно одному из постулатов Бора для стационарных состояний электрона в атоме водорода имеет место соотношение