Both small and large amplitude propagating stalls have been observed experimentally and their characteristics distinguished. The characteristics of the small amplitude propagating stall are such that the phenomenon can be described well by linearized theory. The characteristics of the large amplitude stall (which is the propagating stall phenomenon generally found in compressors) are such that the linearized theory is not adequate to describe the stall.

An apparatus has been constructed to study the formation and dynamics of vortex rings. The rings are formed in water by a momentary jet discharge downward into a glass tank from an orifice in a submerged plate. The necessary impulse is provided by a pressurized reservoir and is controlled by a fast programmable solenoid valve.

In this paper a general equation for calculating the takeoff performance of landplanes is developed in terms of the usual airplane parameters.

The analysis enables the ground effect, wind and atmospheric conditions, altitude, and the use of flaps to be taken into account. A simple and rapid method is presented for the determination of the best flap angle to be used for takeoff.

Experiments have been conducted in the GALCIT Supersonic Shear Layer Facility (S3L) to investigate the behaviour of a flow and geometry with many features that are potentially useful for a Supersonic Combustion Ramjet (SCRAMJET) engine - a recirculation zone for flameholding, enhanced mixing between fuel and air, and low total-pressure losses. In a subsonic diffuser configuration with no mass injection, the exit velocity and guidewall static-pressure profiles collapse over a large range of inlet Reynolds numbers. Significant control of exit velocity and guidewall pressure profiles is possible via injection through a perforated ramp into the freestream. The control authority on the overall pressure coefficient increases with increasing inlet Reynolds number. Simple control volume models put bounds on the overall pressure coefficient for the device.

Steady operation of supersonic diffusers near critical mass flow is interrupted by a transient process known as buzz. This phenomenon consists of a random sequence of individual relaxation cycles. Mass flow entering the diffuser during steady operation is suddenly cut off by a strong interaction between the subcritical shock and boundary layer on the surface of the external compression generator, which blocks the inlet. Air in the plenum chamber, stored at high pressure, then ?blows down? until the inlet can restart. The subsequent supercritical flow entering the diffuser exceeds the flow rate at the exit and the plenum chamber is re-charged to the original condition.