This paper is a comparative study on the characteristics of high-speed liquid jets injected in surrounding water and air using shadowgraph technique. One of the main objectives is to investigate the effects of liquid’s physical properties, used to generate the high-speed liquid jets, on jet generation’s characteristics. Moreover, comparative investigations on effects of those liquid jets after injected in water and air are reported. The high-speed liquid jets were generated by the impact of a projectile launched by a horizontal single-stage power gun. The impact-driven high-speed liquid jets were visualized by shadowgraph technique and images were recorded by a high-speed digital video camera. The process of impact-driven high-speed liquid jet injection in air and water, oblique shock waves, jet-induced shock waves, shock waves propagation, the bubble behavior, bubble collapse-induced rebound shock waves and bubble cloud regeneration were clearly observed. It was found that different properties of liquid (surface tension and kinematic viscosity) affect the jet maximum velocity and shape of the jet. Bubble behaviors were only found for the jet injected in water. From the shadowgraph images, it is found that the maximum average jet velocity, expansion and contraction velocities of bubble in axial direction increase when the value of the multiplied result of surface tension by kinematic viscosity increases. Therefore, surface tension and kinematic viscosity are the significant physical properties that affect characteristics of high-speed liquid jets. Graphic abstract

中文翻译：

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注入水下和环境空气中的冲击驱动高速液体射流的比较可视化研究

本文是利用阴影图技术对喷射到周围水和空气中的高速液体射流特性进行比较研究。主要目标之一是研究用于产生高速液体射流的液体物理性质对射流产生特性的影响。此外，还报告了对注入水和空气后这些液体射流的影响的比较研究。高速液体射流是由水平单级动力炮发射的弹丸撞击产生的。撞击驱动的高速液体射流通过阴影图技术可视化，图像由高速数码摄像机记录。空气和水中的冲击驱动高速液体射流喷射过程，斜激波，射流诱发激波，激波传播，可以清楚地观察到气泡行为、气泡坍塌引起的回弹冲击波和气泡云再生。发现液体的不同性质（表面张力和运动粘度）影响射流的最大速度和射流的形状。仅在喷射到水中的射流中发现了气泡行为。从影图图像中发现，当表面张力与运动粘度的乘积值增大时，气泡在轴向的最大平均射流速度、膨胀和收缩速度增大。因此，表面张力和运动粘度是影响高速液体射流特性的重要物理性质。图形摘要 发现液体的不同性质（表面张力和运动粘度）影响射流的最大速度和射流的形状。仅在喷射到水中的射流中发现了气泡行为。从影图图像中发现，当表面张力与运动粘度的乘积值增大时，气泡在轴向的最大平均射流速度、膨胀和收缩速度增大。因此，表面张力和运动粘度是影响高速液体射流特性的重要物理性质。图形摘要 发现液体的不同性质（表面张力和运动粘度）影响射流的最大速度和射流的形状。仅在喷射到水中的射流中发现了气泡行为。从影图图像中发现，当表面张力与运动粘度的乘积值增大时，气泡在轴向的最大平均射流速度、膨胀和收缩速度增大。因此，表面张力和运动粘度是影响高速液体射流特性的重要物理性质。图形摘要 发现当表面张力与运动粘度的乘积值增加时，气泡在轴向的最大平均射流速度和膨胀收缩速度增加。因此，表面张力和运动粘度是影响高速液体射流特性的重要物理性质。图形摘要 发现当表面张力与运动粘度的乘积值增加时，气泡在轴向的最大平均射流速度和膨胀收缩速度增加。因此，表面张力和运动粘度是影响高速液体射流特性的重要物理性质。图形摘要