排气角度对航行体表面等压气膜演化机制及流动特性影响研究（英文）

Effect of Exhaust Angle on Evolutionary and Flow Characteristics of Pressure-equalizing Film on Surface of Underwater Vehicle

等压排气是一种可有效改善航行体绕流流场特性、抑制纵向偏转的流动控制技术。文章数值模拟了带等压排气的航行体水下垂直运动过程,给出了不同排气角度时的排气流量及速度、气膜长度等参数变化规律,分析了排气角度对等压气膜非定常发展过程及航行体绕流流场特性的影响,建立了排气孔附近及其下游流场、气膜尾部回射流场的拓扑结构,探讨了等压气膜的形态特征、演化规律及其降低航行体表面压力的机制,研究结果有助于深入理解等压排气技术改善航行体流体动力学特性的物理本质。

Pressure-equalizing exhaust is an effective flow control technique to improve the hydrodynamic characteristics of underwater vehicles and to inhibit their pitching moment. In this paper, numerical simulation is conducted to study the underwater vertical movement process of an underwater vehicle with pressure-equalizing exhaust. The variation of the flow rate and velocity of the exhaust as well as the film length under different exhaust angles are given. The influence of the exhaust angle on the unsteady development of the pressure-equalizing film and the hydrodynamic characteristics of the flow field around the vehicle is analyzed. The topological structure is established for the flow field near and downstream the exhaust hole as well as the reentrantjet field at the film tail. Besides, the shape feature and evolution of the pressure-equalizing film and its mechanism to reduce the pressure on the surface of underwater vehicles are discussed. The results are helpful for looking further into the physical nature of the improvement in the hydrodynamic characteristics of underwater vehicles by means of the pressure-equalizing exhaust technique.