Solution of the compressible Rayleigh problem involving an impulsively moved flat plate indicates that transverse velocities can be generated by a purely longitudinal shearing motion. It would be desirable to demonstrate the existence of these waves, and to do so was the motivation for the present investigation. However, the geometry for the Rayleigh problem is prohibitive; and since it was noticed that a similar behaviour should occur for the case of unsteady compressible Couette flow, this was considered for the present investigation. An experimental search for the existence of the transverse velocities was conducted using concentric rotating cylinders to generate the flow. Since these transverse velocities were too small to be measured directly, a temperature gradient was created across the annulus to take advantage of the much greater sensitivity of a hot-wire to temperature fluctuations produced by the fluctuation in the transverse velocity. The periodic temperature fluctuations noted were converted to equivalent transverse velocities. Experimental values obtained agreed qualitatively with the theory. Finally, the role of extraneous effects in the experimental apparatus was considered.

This paper describes an investigation of the turbulent forced plumes generated by steady release of mass, momentum and buoyancy from a source situated in an extensive region of uniform or stably stratified fluid. The treatment, which is an extension of earlier work on buoyant plumes, also brings out the relationship between the jet and the Plume as special cases of forced plumes.

The analysis shows that the behaviour of a forced plume from a source of finite size which delivers buoyancy, mass and momentum can in a uniform environment be related to that from a virtual point source of buoyancy and momentum only, and a treatment is given for the latter type of forced plume. When the environment is weakly stratified it is inferred that forced plumes can be related to point definitely; but when the environment is stably stratified, increasing the release of mass and momentum from a given source of buoyancy has the effect at first of reducing the total height of the plume, and only for very large flux of momentum does the height increase again, without limit. A description is given for the behaviour of vertical jets in a stably stratified environment, and for forced plumes of fluid with negative buoyancy.

By using methods well known in boundary layer theory, the pressure across a contact region is shown to be approximately constant. A partial differential equation for the temperature is then derived. If the ideal-gas flow external to the contact region is known, the temperature profile can be determined. This can then be used to calculate successively the velocity and a better approximation for the pressure of the gas in the contact region. The theory is illustrated by obtaining the temperature, velocity and pressure distributions for a gas in a contact region moving with uniform velocity. The thermal conductivity of the gas is assumed to vary with the temperature τ like k = knτn, where n = 0, 1 or 2. The results are valid for any temperature ratio across the region.

The general theory is also used to determine the motion of a plane shock which is reflected from a plane-conducting wall. The fluid between the reflected shock and the wall is at a higher temperature than that of the wall and a contact region adjacent to the wall results. Expressions for the temperature, velocity and pressure of the fluid are derived, and it is shown that the effect of heat conduction is to decrease the velocity of the reflected shock by an amount which varies as the inverse square root of the time.