绕回转航行体通气空泡末端泄气模式研究

通过布置在水下回转航行体表面的排气缝向已有自然空泡内通气,形成通气空泡,可改善航行体所受流体动力。基于试验研究和数值计算方法,分析通气空泡在傅汝德数(重力)、通气率共同影响下的形态特征和稳定性机理。结果表明,在不同傅汝德数和通气率下,空泡呈现两种不同的流动状态:一种是空泡在航行体表面不闭合,在回转航行体上部形成对涡结构,末端呈涡管状泄气模式;另一种是空泡末端闭合在航行体表面,形成反向回射流,在回射流的切割作用下,空泡会出现断裂和脱落,空泡呈非定常发展,末端呈回射流闭合模式。研究结果为水下航行体流体动力控制方法设计提供指导。

Research on Gas Leakage Mechanism of Ventilated Cavitating Flows Around An Axisymmetric Body

Ventilated cavity formed by the gas which vent through the air gap which set on the submarine vehicle. Base on experiment and numerical simulation, this paper studies the shape and stability of the cavity influenced by Fr and ventilation rates. There are two flow states of the ventilated cavity. The first state is that the ventilated cavity doesn't closed on the axisymmetric body, form vortex structures on the upper part of axisymmetric body, the gas leakage from the tail of the cavity in the mode of vortex-pipe; the second state is that the ventilated cavity closed on the axisymmetric body, and he re-entry jet formed at the end of the ventilated cavity, the gas and water fixed in the internal of the ventilated cavity, the ventilated cavity become instability as the re-entry jet strike on the surface of the ventilated cavity the gas leakage from the tail of the cavity in the mode of closed re-entry.