Application of Measurement-Uncertainty Analysis to Resistance and Self-Propulsion Tests of Ship Model

Abstract

Uncertainly analysis (UA) is applied to the resistance and self-propulsion tests of a ship model, in which the problem of measuring object, the treatment of low-pass filter, the problem of curve-fitting process, etc. are dealt with. The present paper also corrects some parts in the authors' previous paper on the UA for resistance test, and applies the method further to propeller-open and self-propulsion tests. The importance of choosing appropriate object item for uncertainty analysis, i.e., time-mean or instantaneous value, is emphasized. Authors evaluate a new error term S_F in curve fitting process, as well as the standard estimated error SEE. And a consideration is made on the error and its propagation when a low-pass filter is installed in the measuring system. Examples of UA are shown in tables and figures, in which error sources, estimated errors, their propagation route, and sensitivities to the UA items are listed and illustrated. Although the value of the errors themselves are not so small as expected, it is found that UA is quite useful for detecting dominant error sources as well as for obtaining the error values.