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The two compulsory conditions for boundary layer separation are fluid viscosity and positive pressure gradient. By designing the shape of a vehicle so that its surface has a negative pressure gradient area as large as possible, the flow transition and separation are delayed so as to achieve the purpose of drag reduction. Based on the theoretical flow non-separation shape design method of slender bodies, the shape of a vehicle with a critical speed of 100 m/s was designed, and numerical simulation was used to analyze its flow characteristics at different speeds and angles of attack. It is found that the simulation results at zero angle of attack are consistent with those of the theoretical calculation, which proves that the surface of the vehicle can be in a state of non-separation of laminar flow through the shape design. A small attack angle will not destroy the fluid adhesion state on the surface of the vehicle, but whirlpools will appear in the flow when the attack angle is greater than 2 degrees.
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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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