Experimental study on the trajectory of projectile water entry with asymmetric nose shape

Abstract

In this study, we investigated the water entry trajectory characteristics of a projectile with an asymmetric nose shape at different initial impact velocities and impact angles experimentally. With high speed photography, the water entry cavities and projectile motions were captured to obtain the trajectory curve and the attitude angle of the projectile. Compared to the projectile with a flat nose shape, the experimental results presented that the trajectory of the projectiles with asymmetrical nose shapes shows obvious deflection during the water entry process, and the deflection amplitude of the trajectory increases as the cut angle decreases under the same water entry conditions. It is found that the change trend of the projectile’s attitude angle is the almost same under different impact angle conditions. In addition, for the same type of asymmetric nose shape, the trajectory deflection increases with the increase in impact velocity. Finally, a theoretical model of the water entry trajectory was established to predict the projectile motion and trajectory of the projectile with an asymmetric nose shape before the tail-slap process. We compared the experimental data with the calculated results, and the theoretical calculation gave a good approximation with the experimental results. The maximum error of the displacements between the theoretical results and the experimental results is only 3.25%.

Investigation of free surface effect on the cavity expansion and contraction in high-speed water entry

“…(Seddon & Moatamedi 2006;Fang et al 2022;Ju et al 2023;Kong et al 2023;Sun et al 2023;Zhao, Yang & Ming 2023a). High-speed water entry is a transient and strongly nonlinear process involving crossing air and water interfaces, and many complex flows, such as violent water surface splashing and various characteristics of cavity evolution, always occur; these flows are strongly related to the strong impact loads and drastic motions of the body entering the water (Truscott, Epps & Belden 2014;Shi, Hua & Pan 2020;Sui et al 2023). Fully understanding the flow mechanism of the water-entry cavity is an important research direction.…”

Parallel water entry: Experimental investigations of hydrophobic/hydrophilic spheres

“…Nevertheless, several researchers have also focused on investigating water entry phenomena involving objects with non-spherical geometries. Examples of such objects include conical and wedge-shaped projectiles, [37][38][39][40][41][42][43] flat plates, 1,14,[44][45][46][47][48] vertical cylindrical and slender bodies, 8,32,[49][50][51][52] bodies with asymmetric nose shapes, 53 and thick and thin hollow objects. [54][55][56][57][58] Moreover, studies have explored the water entry behavior of objects with more complex geometries, such as 3D-printed birds and teardrop-shaped objects.…”