Superventilated flow past delta wings

Abstract

Although delta wings have been known for some time in aeronautics (1)(2) their introduction into a hydrodynamic context has been quite recent. As in the flow of air, the delta wing provides a simple but useful configuration for investigating three-dimensional problems in cavity flows. At the start of the present work (1960), only one theoretical study on this subject was known (3). No information on flow patterns, force characteristics or other properties were available for these shapes. It was accordingly decided to embark on an experimental program with the aim of providing the basic characteristics of the cavitating flow past delta wings, to observe and outline any interesting features of these flows and, finally, to provide a physical basis for any mathematical analysis of the flow that might be undertaken. Measurements of lift, drag and pitching moment and pressure distributions were made on a family of simple flat plate delta shapes of varying apex angle; several configurations outside this family were also tested. These included a diamond plan form, reverse delta, and a delta with a 90 degree bottom. All were without camber and were tested with no yaw angle. After completion of this work, the exhaustive treatment of Reichardt and Sattler (4) appeared which also deals with cavitating delta wings. It is believed, however, that the current report and that of Reichardt are sufficiently different in scope and method to justify the presentation of the present results.