THE HYDRODYNAMIC CHARACTERISTICS OF A SUBMERGED LIFTING SURFACE HAVING A SHAPE SUITABLE FOR HYDRO-SKI APPLICATION

摘要

An experimental investigation was made to determine the hydrodynamic characteristics of an aspect-ratio-0.25 lifting surface having a shape suitable for hydro-ski application and operating at various depths of submersion. Comparisons were made between these data and data previously obtained on a rectangular modified flat plate having an aspect ratio of 0.25 and the same plan-form area. The comparisons indicated that the hydro-ski model had a lower angle of zero lift, a lower lift-curve slope, a lower lift coefficient at the high angles of attack, and a lower lift-drag ratio.nAt high angles of attack and high speeds, cavitation at the leading edge caused a large decrease in lift coefficient. At shallow depths of submersion an unstable flow condition was encountered during cavitation because, of small amounts of air bleeding intermittently into the cavitated region through the trailing vortices and then being dissipated by entrainment in the water;thus a fluctuating pressure in the cavity on the upper surface of the model resulted.