The impinging pressure of a water jet is a key factor in engineering applications, and the jet shape has a great influence on this pressure. In this paper, five different nozzle shapes were designed, and impacting tests were conducted based on a self-designed experimental platform using a PVDF piezoelectric film sensor and a high-speed camera to record the impacting data. Additionally, the computational fluid dynamics (CFD) method was also applied to study the velocity distribution. The results show that the pressure profiles of different water jet shapes impacting onto a solid surface present a consistent pattern, namely, an initial transient and enormous peak pressure and then a longer and smaller stagnation pressure. Although the stagnation pressure in this paper is not sufficiently obvious, the peak pressures of the five water jet shapes are much different from one another. Under the same inlet pressure, the peak pressure of the circular water jet is the largest, and those of the square, triangular, cross-shaped, and elliptical water jets decrease in turn. The flowing regimes captured by the high-speed camera together with the CFD simulation results indicate that the discrepancy in the peak pressure may be a combined action of the liquid velocities and jet head shapes.

中文翻译：

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不同喷嘴孔口形状的高压水射流冲击性能

水射流的冲击压力是工程应用中的一个关键因素，射流的形状对这个压力有很大的影响。本文设计了五种不同的喷嘴形状，并基于自行设计的实验平台进行了冲击试验，利用PVDF压电薄膜传感器和高速相机记录冲击数据。此外，还应用了计算流体动力学 (CFD) 方法来研究速度分布。结果表明，冲击固体表面的不同水射流形状的压力分布呈现出一致的模式，即初始瞬态和巨大的峰值压力，然后是更长更小的停滞压力。虽然本文的停滞压力不够明显，五种水射流形状的峰值压力彼此大不相同。在相同的入口压力下，圆形水射流的峰值压力最大，方形、三角形、十字形和椭圆形水射流的峰值压力依次减小。高速相机捕获的流动状态以及 CFD 模拟结果表明，峰值压力的差异可能是液体速度和喷头形状的共同作用。