High-speed oblique water entry is an interesting subject, many physical aspects of which remain unknown up to now. Among high-speed air-to-water projectiles, the supercavitating cylindrical-cone (SCC) ones have economic and operational advantages over the other types. However, maintaining stability of the SCC projectiles inside the cavity at shallow entry angles is a challenging issue from both practical and design-related points. The first section of the present study proposes a novel and unique scheme of air-to-water supercavitating projectile design which is called the supercavitating stepped cylindrical-cone (SSCC) projectile. The SSCC scheme is analyzed numerically to investigate the projectile stability improvement at shallow entry angles. The 6DOF dynamics of the SSCC projectile are investigated using the Star-CCM+ commercial code in the presence of three phases of air, water and vapor in a three-dimensional and transient model. Accuracy of numerical results and the model’s ability to simulate the physical phenomena of water entry is validated using experimental results from the literature, and both are in good agreement. In the present study, the high-speed oblique water entry dynamics of the SSCC projectile are investigated for five certain entry angles varying from 10° to 60°. The results show that the SSCC projectile faces intensive unstabilizing forces in the water entry process which leads to a heavy pitching moment and, hence, intensive angular velocity (\( \dot{\gamma } \)) on the projectile. This study also proves that the presence of step enhances the projectile stability in the entry process. The present study shows that, based on their geometry and mass characteristics, each SSCC projectile is capable of withstanding instability up to a critical value of the angular velocity (\( \dot{\gamma }_{\text{Cr}} \)). Therefore, projectile stability inside the cavity can be achieved when the value of maximum angular velocity (\( \left| {\dot{\gamma }} \right|_{\hbox{max} } \)) experienced by the projectile is lower that \( \dot{\gamma }_{\text{Cr}} \) (i.e., \( \left| {\dot{\gamma }} \right|_{\hbox{max} } < \dot{\gamma }_{\text{Cr}} \)). The results of this study also show that \( \left| {\dot{\gamma }} \right|_{\hbox{max} } \) is inversely correlated with the \( \gamma \), and that it follows a simple equation which is proposed in this study. Therefore, projectile stability inside the cavity can also be practically achieved by adjusting the shooting mechanism at an angle higher than the minimum stable entry angle (\( \gamma_{\hbox{min} } \)). This study also proposes an effective numerical approach to evaluate \( \gamma_{\hbox{min} } \) of a supercavitating projectile. It should be noted that determining the value of \( \gamma_{\hbox{min} } \) is an important factor from both a practical and design-related points of view.

高速倾斜水进入是一个有趣的主题，到目前为止，其许多物理方面仍然未知。在高速空对空射弹中，超空化圆柱锥体（SCC）相对于其他类型具有经济和操作优势。然而，从实用和设计相关的角度来看，保持腔内SCC弹丸在浅进入角处的稳定性都是一个具有挑战性的问题。本研究的第一部分提出了一种新颖的，独特的空水超空射弹设计方案，称为超空空梯形圆锥形（SSCC）射弹。对SSCC方案进行了数值分析，以研究在浅入射角下弹丸稳定性的改善。使用Star-CCM +商业代码，在三维，瞬态模型中存在空气，水和蒸汽的三相的情况下，对SSCC弹的6DOF动力学进行了研究。数值结果的准确性和该模型模拟水进入物理现象的能力已使用文献中的实验结果进行了验证，两者都非常吻合。在本研究中，研究了SSCC弹丸的高速倾斜水进入动力学，研究了五个特定的进入角（从10°到60°）。结果表明，SSCC弹丸在入水过程中会面临强烈的不稳定力，导致沉重的俯仰力矩，因此导致强烈的角速度（数值结果的准确性和该模型模拟水进入物理现象的能力已使用文献中的实验结果进行了验证，两者都非常吻合。在本研究中，研究了SSCC弹丸的高速倾斜水进入动力学，研究了五个特定的进入角（从10°到60°）。结果表明，SSCC弹丸在入水过程中会面临强烈的不稳定力，导致沉重的俯仰力矩，因此导致强烈的角速度（数值结果的准确性和该模型模拟水进入物理现象的能力已使用文献中的实验结果进行了验证，两者都非常吻合。在本研究中，研究了SSCC弹丸的高速倾斜水进入动力学，研究了五个特定的进入角，其变化范围为10°至60°。结果表明，SSCC弹丸在入水过程中会面临强烈的不稳定力，导致沉重的俯仰力矩，因此导致强烈的角速度（在5个确定的10°至60°的入射角下，研究了SSCC弹丸的高速斜入水动力学。结果表明，SSCC弹丸在入水过程中会面临强烈的不稳定力，导致沉重的俯仰力矩，因此导致强烈的角速度（在5个确定的10°至60°的入射角下，研究了SSCC弹丸的高速斜入水动力学。结果表明，SSCC弹丸在入水过程中会面临强烈的不稳定力，导致沉重的俯仰力矩，因此导致强烈的角速度（\（\ dot {\ gamma} \））。这项研究还证明，台阶的存在增强了进入过程中的弹丸稳定性。本研究表明，基于它们的几何形状和质量特性，每个SSCC弹丸都能够承受高达角速度临界值（\（\ dot {\ gamma} _ {\ text {Cr}} \）的不稳定性）。因此，当射弹所经历的最大角速度（\（\ left | {\ dot {\ gamma}} \ right | _ {\ hbox {max}} \）的值是降低\（\ dot {\ gamma __ {\ text {Cr}}} \）（即\（\ left | {\ dot {\ gamma}} \ right | _ {\ hbox {max}} <\ dot {\ gamma} _ {\ text {Cr}} \））。这项研究的结果还显示\（\ left | {\ dot {\ gamma}} \ right | _ {\ hbox {max}} \）与\（\ gamma \）成反比，并且遵循本研究中提出的一个简单方程式。因此，通过以高于最小稳定进入角（\（\ gamma _ {\ hbox {min}} \））的角度调节射击机构，实际上也可以在腔体内实现弹丸稳定性。这项研究还提出了一种有效的数值方法来评估超空化射弹的\（\ gamma _ {\ hbox {min}} \）。应该注意的是，从实用和与设计相关的角度来看，确定\（\ gamma _ {\ hbox {min}} \）的值都是重要因素。