A counter-current jet (CCJ) is significantly different from a classical jump – it is like a classical jump with a reverse surface jet layer above it. A series of experiments, with the jet's Froude number in the range 4–10, was conducted to investigate the velocity distribution characteristics of CCJs. It was found, compared with a classical jump, the CCJ velocity distribution was more even and the decay of the maximum velocity was more efficient. It was beneficial to the energy dissipation and the deceleration of a high-speed flow. The variations of velocity with depth were opposite in the upper and lower parts of the zero-velocity line, resulting in relatively large fluid internal friction near the zero-velocity line. The internal friction between the surface jet layer and the lower fluid also increased the energy dissipation rate. A counter-current energy dissipator was found to achieve a good energy dissipation effect without auxiliary energy dissipators, which could be beneficial to engineering applications.

中文翻译：

---

逆流射流​​的速度分布特征

逆流喷射 (CCJ) 与经典跳跃明显不同——它就像经典跳跃，上面有一个反向表面喷射层。进行了一系列实验，射流的弗劳德数在 4-10 范围内，以研究 CCJ 的速度分布特征。结果发现，与经典跳跃相比，CCJ 速度分布更均匀，最大速度衰减更有效。有利于能量耗散和高速流的减速。速度随深度的变化在零速度线的上部和下部相反，导致零速度线附近的流体内摩擦较大。表面射流层与下部流体之间的内摩擦也增加了能量耗散率。