예인수조에 대수속도계 설치를 위한 타당성 조사

Abstract

A circulating current called residual current is generated by the repeated towing of a model ship in a towing tank. Since its presence would produce a discrepancy between ground and water speeds and cause an unstableness of test results, the measurement of water speed is important for the reliable model tests. It needs highly accurate measurement because the speed of residual current is only several to 10 mm/s. Moreover, as the resistance of a model ship is affected by wake of current meter, careful consideration should be taken for the adoption of water speed measured with current meter. In this paper, the calibration results and the measurement accuracy of the propeller type current meter are presented. The depthwise distributions of residual current at several longitudinal positions of the KRISO towing tank are shown. Finally, the results of model tests with the propeller type current meter for two different ships are discussed.