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As one of the representative types of high-speed surface craft, stepped planing crafts have strong nonlinear hydrodynamic problem when sailing at high speed. It is a research focus to predict the craft's resistance and motion response accurately. Based on the viscous fluid theory and dynamic mesh techniques, the paper presents the coupling solution of the longitudinal three degrees of freedom motion equations of stepped planing crafts. A set of numerical prediction methods for a stepped planing craft were established. The numerical predictions of the stepped planing craft resistance and navigation attitude at different speeds were carried out, and the variation characteristics of the resistance and navigation attitude of the stepped planing craft with speed were quantitatively analyzed. The distribution law of sliding surface, bottom pressure and flow field was discussed. The results show that when Fr▽<4.88, the pressure difference resistance coefficient Cp is greater than the friction resistance coefficient Cf, with the pressure difference resistance being a dominant component. When Fr▽≥4.88, Cp is slightly smaller than Cf, and the friction resistance Rf is equivalent to the pressure difference resistance Rp. The wetted area ratio ζ decreases rapidly with the increase of speed. When Fr▽≥4.48, ζ tends to be stable at about 0.31. The research results of this paper are of important value to the design of the stepped planing crafts.
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| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |
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