Shigeki Morioka

Magnetohydrodynamic Shock Polar

The steady shock discontinuity in the flow of a perfectly conducting gas with aligned magnetic field is considered by taking, as the parameters, the Mach number and the Alfven number ahead of the shock and the shock angle. The jumps across the shock, which satisfy the various conservation laws as well as the entropy and evolutionary conditions, are calculated by making use of an electronic computer. The possible types of MHD shock polar are shown in the speed-deflection plane for various combination of parameters.

Non-Equilibrium Flow of a Weakly Ionized Gas past a Magnetized Wall

The non-equilibrium effect in the two-dimensional, steady flow of an ionizing gas past a magnetized wall is considered on the basis of the linearized theory. A simple approximate solution is derived for an argon-like idealized gas by making use of some character of its ionization. As an example, the velocity distribution along the wall and the slope of a stream line are calculated for both subsonic and supersonic flows past a plane wall containing a circular magnetic field. It is shown that the non-equilibrium process has no serious effect upon the flow field.

Two-Dimensional Flow of a Weakly Conducting Gas Past a Plane Wall Containing a Magnetic Dipole

In order to find some effects of compressibility on the flow of a conducting gas past a magnetized body, the two-dimensional, steady flow of a weakly conducting gas past a plane wall containing a magnetic dipole, the axis of which is placed parallel to the wall, is considered on the basis of the small perturbation theory. The boundary value problem in terms of perturbation velocity is formulated and solved for subsonic and supersonic flows. In subsonic flow of a comparatively small Mach number, the drag and moment depend only on a parameter N , where N = R m S , R m is the magnetic Reynolds number and S is the pressure number. In supersonic flow, the velocity distribution on the wall is not monotonus, and becomes more irregular as the Mach number approaches unity.

High Subsonic Flow past a Wedge in a Two-Dimensional Wind Tunnel at its choked State

The two-dimensional high subsonic flow at the choked state past a symmetrical double-wedge profile placed midway between two parallel walls is investigated. The subsonic flow field over the front half of the profile is given by the relaxation solution for a Tricomis boundary value problem in the hodograph plane. The supersonic flow over the rear half is calculated by the method of characteristics. The results for the pressure distribution and the choking Mach number are found to agree well with Marschners analytical results over fairly wide range of the transonic parameter.

On the Shock Configuration in a Perfectly Conducting Gas in the Presence of a Uniform Magnetic Field

If a two-dimensional body is placed in a steady, uniform flow of a perfectly conducting gas in the presence of a uniform magnetic field parallel to the flow, an attached or detached shock configuration must occur for certain values of the Mach number and the Alfven number at infinity upstream. The shock wave can be transformed into the shock polar. Mathematical relations are given, anid the kind of configuration can thus be determined. New types of configurations are found and discussed. Results of calculations are presented in graphical form. (L.N.N.)

Jets of a Perfectly Conducting Inviscid Gas in the Presence of a Magnetic Field parallel to the Stream

The two-dimensional and the axially symmetrical jets of a perfectly conducting inviscid gas in the presence of a magnetic field parallel to the stream are investigated on the basis of the linearized theory, when the jets are governed by the supersonic hyperbolic equation. To this approximation, the fundamental equations and the boundary conditions are found to agree in their forms with those in the ordinary gasdynamic case, except for some parameters. Therefore, it is possible to obtain the solutions at once by making suitable substitution of the parameters in the well-known solutions for the gasdynamic case. However, when the surrounding flow is governed by the subsonic hyperbolic equation, the circumstance is somewhat different from the gasdynamic case because disturbances in the surrounding flow propagate along the upstream characteristics. The structure of such a jet in the two-dimensional case is re-examined from the view point of reflection and refraction of a weak plane shock wave incident upon an ...

Propagation of a Disturbance through a Separated Gas-Liquid System

The disturbance propagating through a simple separated gas-liquid system is considered on the basis of the linearized theory in the ordinary gasdynamics. The two-dimensional and unsteady field is analyzed by using the Laplace-Fourier transform technique, and the asymptotic solution expanded in powers of the ratio of the gas density to the liquid density is discussed. It is shown that the initial disturbance is subjected to a change in shape in the course of time and that the propagation aspect differs depending on the type of the disturbance. The separated gas-liquid system has a dispersion property.

Finite Larmor Radius Hydromagnetic Flow past an Obstacle

Effects of dispersion due to the finite Larmor radius on the steady flow of a collisionless plasma past a thin symmetrical semi-infinite wedge are considered on the basis of the modified Chew-Goldberger-Low theory. The flow field near the tip is given by the numerical integration of the Fourier transform. The asymptotic behaviour of the flow field at a far distance from the wedge is estimated by using the method of stationary phase or Laplaces method. It is shown that the flow field is subject to remarkable variety of dispersion effect according to the main flow conditions.

Flow of a Conducting Gas past Thin Wedge

The steady flow of an ideal gas with finite conductivity past a thin symmetrical semi-infinite wedge in an aligned magnetic field is considered. The wedge is assumed to be perfect conductor or insulator. The asymptotic properties of the flow field near and far from the wedge are investigated for the various values of Mach number, Alfven number and magnetic Reynolds number of the free stream. Several informations are obtained about the structure of the weak magnetogasdynamic shock layer influenced by the boundary.

Two-Dimensional Unsteady Flow of a Weakly Conducting Fluid Past a Plane Wall Containing a Variable Magnetic Dipole

The two-dimensional unsteady flow of a weakly conducting perfect fluid past a plane wall in a magnetic field, with the intensity varying with time, is considered on the basis of the small perturbation theory. The initial and boundary value problem for perturbation quantities is formulated and solved for a magnetic dipole produced by a direct or an alternating current which has been switched on. The initial state of the vorticity distribution in the flow develope by such a non-uniform magnetic field is discussed in detail.