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In order to analyze the impact attack angle on the oblique water-entry performance of projectiles, the oblique water-entry tests of a projectile under multiple conditions were carried out based on the high-speed photography technology. The effects of the attack angle on the cavity evolution and motion characteristics of the projectile were studied. Based on finite volume method and overlapping grid technology, a numerical method for oblique water-entry of projectiles was established. The water-entry stability and force characteristics of the projectile were compared and analyzed with the attack angle set as 0°, ±0.5°, ±1.5°, ±2.5°, and ±3.5° respectively. The reliability of numerical simulation was validated by comparing the simulated results with the experimental results. It is shown that when the attack angle is positive, the projectile will deflect counterclockwise and deviate upward, while it will deflect clockwise and deviate downward when the attack angle is negative. When the attack angle is zero, the projectile motion is stable, and the simulation results under the same condition are consistent with the experimental ones. With the increase of the absolute value of the attack angle, the absolute value of the deviation and deflection of the projectile presents an increasing trend simultaneously, and the time of the tail-slapping of the projectile is gradually advanced. When the absolute value of the attack angle is the same, the first tail-slapping of the projectile occurs earlier when the attack angle is less than 0°, and the water-entry stability of the projectile is worse. Influenced by the attack angle, both the drag and lift of the projectile will shock violently at the early stage of water-entry. With the increase of the attack angle, the lift of the projectile presents a decreasing trend, while the drag is not significantly influenced by the attack angle, except that the drag is relatively large at attack angle of −3.5 °.
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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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