Effects of Aspect Ratio, Section Shape, and Reynolds Number on the Lift and Drag of a Series of Model Control Surfaces.

摘要

The report presents the results of towing tank tests on a series of fins, representative of the canards on a SWATH vessel or the rudders on a planing hull. The work was done to determine whether or not the fins and rudders on a small model suffered from serious scale effects. Fins with aspect ratios of 1.0, 1.5 and 2.0 were mounted vertically under a horizontal flat plate and towed at a series of speeds resulting in five Reynolds numbers, based on chord length, between 42,000 and 150,000. The fins had both flat plate and NACA 0015 cross sections, and were tested with and without turbulence trips. Lift and drag forces were measured at a series of angles of attack which were varied from 0 to 35 degrees in five degree increments. The measured lift slopes agreed well with predictive equations developed at DTNSRDC for fins at high Reynolds numbers. This means that dynamic stability and course keeping data taken using small models can be used in making full scale predictions. Control surfaces, Reynolds number effects, Fins, Turbulence trips, SWATH Control, Rudders, Aspect ratio effects.