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When an underwater vehicle navigates near a wall, the flow field around the underwater vehicle will be changed, which greatly affects its stability and maneuverability. Based on the CFD method, the hydrodynamic performance, including straight-ahead performance, oblique navigation performance, was analyzed under the conditions of near upper wall, bottom wall and vertical narrow channel. Finally, the following conclusions are drawn: when the underwater vehicle sails at a constant speed near the upper or bottom wall, it generates increased resistance, body suction and tail suction. When the vehicle approaching the upper wall at different distances, the directions of vertical force and pitching moment will be changed, and the ratio of direction transition interval is between 5-6 and 3-4, respectively. When the underwater vehicle sails at a constant speed near the vertical narrow channel, the influence of the wall effect on its vertical force and pitching moment has a relatively obvious competition relationship, and the competitive percentage accounts for about 50%. All hydrodynamic coefficients can be fitted by quadratic polynomials based on the reciprocal of the spacing ratio. The hydrodynamic coefficient of wall effect can be obtained from a graph by monitoring the combinations of different upper and lower spacing ratios when simulating the maneuverability of underwater vehicles.
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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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