Fully Cavitating Hydrofoil Response to Streamwise Sinusoidal and Sharp-Edged Gusts at Zero Cavitation Number.

摘要

A second-order linearized theory of two-dimensional cavity flows is used to study the nonsteady response of hydrofoil lift and moment to sinusoidal and sharp-edged streamwise gusts. The analysis is restricted to the case of zero cavitation number corresponding to an infinitely long cavity in an otherwise unbounded flow. For sinusoidal gusts, lift and moment response functions are presented for the entire range or reduced frequency. In addition, transient lift and moment responses are tabulated for the reactions which occur after the foil encounters a sharp-edged gust. These calculations are carried out for those terms in the solution which result from the nonsteady downwash on the wetted surface of the foil which are due to the direct action of the gust on the inclined wetted surface. They provide a direct cavity flow analog of the Horlock function of airfoil theory. The present study of a cavity flow has revealed an added nonsteady effect resulting from an interaction between the gust and the cavity.