Flow control techniques play an important role during water entry. In this paper, the idea of water entry of the projectile with single canard-wing is proposed and applied to the water entry problem. The cavity evolution and motion characteristics of projectile with canard-wing were investigated through experiments, and the cavity length, trajectory, and attitude changes of projectile with canard-wing during water entry were quantified. The results show that, different from the water entry process of projectile without wing, the projectile with canard-wing has the typical characteristics of forming the attached cavity on the wing. Due to the influence of canard-wing, the trajectory deflection is always toward the side without the wing, and the initial moment of trajectory deflection is advanced with the increase in the impact velocity. The length of the fore-end cavity and the attached cavity on the wing increases as the impact velocity increases and the pinch-off depth of the fore-end cavity also increases. Moreover, the deviation of the trajectory and the attitude angle of the projectile with canard-wing increases as the impact velocity increases during water entry. The results can provide important support for the passive flow control during the water entry of the projectile and the development of the trans-media aircraft.

中文翻译：

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鸭翼弹丸垂直入水实验研究

流量控制技术在进水过程中发挥着重要作用。本文提出了单鸭翼弹丸的入水思想，并将其应用于入水问题。通过实验研究了鸭翼弹丸的空腔演化和运动特性，量化了鸭翼弹丸入水时的空腔长度、弹道和姿态变化。结果表明，与无翼弹丸的入水过程不同，鸭翼弹丸具有在翼片上形成附腔的典型特征。由于鸭翼的影响，弹道偏转始终向无机翼一侧偏转，且弹道偏转初始时刻随着撞击速度的增加而提前。随着冲击速度的增加，前端空腔和机翼上的附着空腔的长度增加，前端空腔的夹断深度也增加。此外，鸭翼弹丸入水时，随着冲击速度的增大，弹道偏差和姿态角也随之增大。研究结果可为弹丸入水过程中的被动流动控制以及跨介质飞行器的研制提供重要支撑。