Nonequilibrium Ionization Behind a Strong Shock Wave in the Mars Atmosphere

The paper reports results of experimental and numerical studies of nonequilibrium ionization behind a strong shock wave in the Mars atmosphere. The calculated kinetic model is verified by measuring the electron concentrations and temperature in the relaxation zone     

Interaction of Small Hydrodynamic Perturbations with a Nonequilibrium Region in a Gas Flow

The problem of interaction of small hydrodynamic perturbations with a nonequilibrium region in a Gas flow with different models of energy pumping is solved. One-dimensional and two-dimensional interactions are considered. A range of system parameters is found in which interaction occurs in a resonant manner (significant amplification of perturbations is observed). It is demonstrated that interaction of vortex perturbations with the nonequilibrium region generates heat waves. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 46, No. 6, pp. 58–64, November–December, 2005.     

Interaction of shock waves with a combined discontinuity in two-phase media. 2. Nonequilibrium approximation

Interaction of a shock wave and a motionless combined discontinuity separating two twocomponent mixtures with different initial volume concentrations is studied on the basis of numerical simulation of unsteady processes. The calculations were performed using a modified method of coarse particles and a highaccuracy TVD difference scheme adapted to calculation of twophase flows. Flow parameters determined by analytical dependences coincide with those obtained by numerical simulation at large times of the process. Upon interaction of the shock wave and the combined discontinuity, the type of the transient or reflected shock wave may coincide with or differ from the type of the incident shock wave. The possibility of existence of a pressure difference at the combined discontinuity boundary, which was earlier predicted analytically, is confirmed.     

Interaction Between a Slow Magnetohydrodynamic Shock Wave and a Tangential Discontinuity

The self-similar problem of the oblique interaction between a slow MHD shock wave and a tangential discontinuity is solved within the framework of the ideal magnetohydrodynamic model. The constraints on the initial parameters necessary for the existence of a regular solution are found. Various feasible wave flow patterns are found in the steady-state coordinate system moving with the line of intersection of the discontinuities. As distinct from the problems of interaction between fast shock waves and other discontinuities, when the incident shock wave is slow the state ahead of it cannot be given and must to be determined in the process of solving the problem. As an example, a flow in which the slow shock wave incident on the tangential discontinuity is generated by an ideally conducting wedge located in the flow is considered. The basic features of the developing flows are determined.     

Interaction of a Streamwise Vortex with an Oblique Shock Wave

Interaction of a supersonic streamwise vortex with an oblique shock wave is considered. A mathematical model of the streamwise vortex is constructed. Three interaction regimes (weak, moderate, and strong) are found. It is shown numerically that vortex breakdown is possible in the case of strong interaction. The influence of the governing parameters on the interaction type is studied. It is shown that the main effect on the interaction type is exerted by the streamwise velocity and angle of the wedge forming the shock wave. The effect of splitting of the primary vortex on the shock wave in the case of moderate and strong interaction regimes is found.     

Travelling Wave Solutions in a Tissue Interaction Model for Skin Pattern Formation

We discuss the existence and the uniqueness of travelling wave solutions for a tissue interaction model on skin pattern formation proposed by Cruywagen and Murray. The geometric theory of singular perturbations is employed.     

Interaction of a Shock Wave with a Spherical Gas–Liquid Cluster

Experimental studies were performed of the interaction of a plane shock wave with a spherical gas–liquid cluster (polyurethane foam ball saturated with a bubbly liquid) in a vertical shock tunnel filled with a liquid. The cluster was shown to generate a solitary pressure wave of large amplitude.     

旋涡与行进表面水波相互作用的实验研究

采用振动板式造波器在二维水槽中生成近似单色的行进表面水波，采用夹板式涡发生器生成稳定上浮的涡对，在Ｆｒｏｕｄｅ数约为０．５的条件下，得到了水下涡对与不同波长和振幅的行进表面水波相互作用时的干扰图象，以实验方法验证了理论分析和数值计算的结果，并为进一步研究旋涡与行进表面水波的相互作用提供了一种实验研究方法     

Nonequilibrium gas-condensate flow in a laval nozzle

A scheme is proposed which simplifies the algorithm and reduces the labor involved in solving the system of quasi-linear hyperbolic equations describing supersonic nonequilibrium two-phase flow in an axisymmetric nozzle.     

Direct Shocks in a Vibrationally Nonequilibrium Gas

Direct shocks in flows of a high-temperature diatomic gas with rotational and vibrational degrees of freedom are considered. Gas-dynamic parameters and populations of molecular vibrational levels behind a shock are studied for the case of disturbance of vibrational equilibrium in an incident flow.     

管道流固耦合振动的行波方法研究

应用波动方法分析载流管道流固耦合振动问题。采用直梁模型，推导了管道流固耦合系统的轴向、横向波导方程及平面管系的坐标转换矩阵，通过节点位移连续和力平衡条件建立了耦合系统的散射模型。最终分析了两种耦合对载流管道振动的影响机理及流速变化对管道振动稳定性的影响。数值算例表明本文方法的正确性及有效性。     

Karman Vortex Street in a Vibrationally Nonequilibrium Gas

The problem of vibrationally nonequilibrium gas flow past a cylinder with the formation of a Karman street is considered. The effects of relaxation on the flow parameters, namely, on vortex damping and deformation, is analyzed on the basis of a numerical simulation. A theoretical explanation of these effects is proposed.     

Nonequilibrium adsorption of a radioactive gas in a porous medium

An analytical solution is obtained to a system of equations describing the nonequilibrium adsorption of a radioactive gas, which is moving with a constant velocity in a semi-infinite, sorbing medium, for a boundary condition depending arbitrarily on the time. An investigation is made of the case of the nonequilibrium adsorption of a motionless gas. The solution is also investigated for a boundary condition in the form of a δ-function. It is shown that, in distinction from equilibrium adsorption, in the medium there are propagated, generally speaking, two maxima of the concentration, one of which arrives at a given point without a lag, while the second lags. Approximate solutions are obtained for strongly washed-out and δ-shaped pulses.     

Contact Interaction of the Faces of a Penny-Shaped Crack Under a Normally Incident Shear Wave

Consideration is given to the contact interaction of the faces of a penny-shaped crack in three-dimensional space under a normally incident harmonic shear wave. The problem is solved by the method of boundary integral equations. The dependence of the stress-intensity factor on the wave number is analyzed. The results obtained are compared with those neglecting the contact interaction.     

Nonequilibrium degassing of a single-component gas-liquid mixture

At the present time the calculation of the separation of gas-liquid mixtures is carried out according to methods based on the assumption of the existence of phase equilibrium between the liquid and separated gas [1, 2]. However, the validity of this assumption is violated with a decrease of the separation time. In the present work a model and a method of calculating non equilibrium degassing are proposed for the special case of a single-component gas-liquid mixture.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 5, pp. 110–117, September–October, 1976.     

Nonequilibrium radiation of a strong shock wave

We examine the nonequilibrium radiation from the first negative band of the molecular nitrogen ion N ₂ ⁺ . The various N ₂ ⁺ ion excitation mechanisms are discussed. It is shown that for a shock wave velocity in air 8 km/sec the primary excitation mechanism is electronic impact.In conclusion the authors wish to thank V. K. Vertushkin and A. A. Gladkov for supplying the calculations on the structure of the normal compression shock and L. I. Ponomarev for helpful discussions.