| This paper is about an analysis on resistance performances of Small Water-Plane-Area Twin Hull(SWATH), which is comprehensive and systemic.The demihull of SWATH is separated into three parts: entrance, parallel middle body, and run. The linetype of the demihull is approximated through special trigonometric function (Chebyshev Polynomial). Making use of the classical linear wave-making resistance theory, the calculating method about the wave resistance of SWATH is detailedly deduced. The expression of wave resistance is described as quadratic terms, and the viscous resistance is calculated by using empiric formula. In addition, the paper presents the calculation results of the wave and total resistance.Based on the invariability of the strut linetype, fixing location and the main body's principal dimensions, regarding the invariable displacement of the main body as the constraint condition, the wave resistance is reduced by optimizing the main body linetype, and this is carried out through the quadric layout method of variable scale serials. To ensure the longitudinal-aberrance appearance in the optimization, the method through controlling the main body's curve of sectional areas is used. And the optimizing results of the main body are presented in the paper.The resistance tests of the ship model are also carried out, and they includes bare body and entire appendage resistance tests. The test results are expressed by quadric conversion, and the reliability of the theory calculation is validated. In addition, the longitudinal moments of bare body in still water and model with horizontal fin are measured. All these present some references for real ships design.The effects of ship form parameters on wave resistance of SWATH are analyzed, and the select method of the parameters during ships design is presented. Also, the curves about the wave and total resistance varying with ship form parameters are given out in this paper.
|
PDF Full Text Request