THE DESIGN OF TWO DIMENSIONAL LOW DRAG, BASEVENTED STRUTS
HYDRONAUTICS INC LAUREL MD
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Linearized cavity flow theory is used to determine the shape and drag of a series of base-vented strut sections having a prescribed chordwise pressure distribution. Stagnation pressure at the nose of the strut is generated by two methods a flat plate normal to the flow at zero cavitation number, and a parabolic-type nose singularity. The chordwise pressure distributions were specified in the equivalent airfoil plane to be either in the form of a sine series or a symmetrical flat roof top. Numerical calculations were carried out for a series of struts derived by combining the various perturbation flows with the two types of stagnation regions to determine the strut shape, section modulus, minimum pressure coefficient and cavity drag coefficient. Comparison of experimental and theoretical results and the effects of finite base cavitation number and frictional resistance are discussed. Charts for determining the coordinates of the optimum strut for a given design problem are presented.
- Marine Engineering