High-speed Water Tunnel Research Articles

Water Tunnel Techniques for Force Measurements on Cavitating Hydrofoils

The paper reviews briefly experimental techniques and data-correction procedures developed in connection with studies in the High Speed Water Tunnel, California Institute of Technology, for hydrofoil force measurements. The matters discussed relate chiefly to problems of force measurement in cavitating flow and to procedures devised to solve them. Items considered in this connection are water-tunnel balances, the effects of tip-clearance flows, tare corrections, the importance of cavity-pressure measurements, cavitation scaling, tunnel-wall effects, and hydroelastic effects.

Proposed Acoustic System for Ordnance Research Laboratory Water Tunnel

A description is given of the acoustic methods and equipment for detecting and locating sources of cavitation on underwater bodies and propellers (under test) in the high speed water tunnel now under construction at the Ordnance Research Laboratory at the Pennsylvania State College. Sound arising inside the tunnel will pass through an acoustically transparent window to an external tank in which is placed a small piezoelectric crystal hydrophone at the focus of an ellipsoidal reflector. The source of sound can thus be located because the hydrophone is most sensitive to sounds originating at the conjugate focus of the ellipsoid which is inside the tunnel. The reflector and hydrophone assembly has three degrees of freedom.

Laboratory Investigations of the Mechanism of Cavitation

Abstract The paper describes some experimental investigations of the formation and collapse of cavitation bubbles. The experiments were carried on in the high-speed water tunnel of the Hydrodynamics Laboratory of the California Institute of Technology under the sponsorship of the Research and Development Division of the Bureau of Ordnance of the U. S. Navy and the Fluid Mechanics Section of the Office of Naval Research. A detailed study of the formation and collapse of the individual bubbles has been carried on by the use of high-speed motion pictures taken at rates up to 20,000 per sec. From these records calculations have been made of rate of formation and collapse of the bubbles. Deductions have been drawn from these results concerning the physical mechanism of the cavitation phenomenon.