Wind Generation and Calibration in a Conventional Towing Track

Abstract

Over the past three years, the Naval Academy Hydromechanics Laboratory (NAHL) has been investigating the behavior of both intact and damaged ship models in the presence of moderate and severe wind and waves. This paper describes the design, fabrication, calibration, and use of the wind generation system developed for this experimental study. This modular wind generation system consists of up to four centrifugal fan sets suspended across the towing tank on a system of trusses. The discharge of each fan set is vectored (vertically) by adjustable louvers and throttled by means of an internal baffle. Wind velocity is measured at selected locations by a set of miniature vane anemometers. This collection of anemometers is used to map the towing tank's wind field longitudinally, vertically and transversely. Significant differences exist in the spatial distribution of the wind velocity and its quality between the NAHL wind field, theoretical assumptions, and the real world. These differences are described. In addition, decisions, observations, and ramifications regarding the scale modeling of a wind field, in conjunction with pragmatic model testing in a conventional towing tank, are discussed.