针对垂直发射条件下通气云空泡的流动特性,以水下航行体为研究对象,采用改进型延迟分离涡模型(IDDES)进行非定常数值模拟,通过引入混合尺度加速了雷诺时均(RANS)到大涡模拟(LES)的转换计算,提高了湍流应力的计算精度;同时搭建了垂直约束式水下发射平台,采用定量排气的方式研究了通气云空泡的发展过程,验证了数值方法的有效性.研究发现:气液交界面在旋涡流动的作用下发生失稳,部分水相通过气液界面汇入通气空泡中发生气液掺混,形成云空泡;云空泡的发展为尺寸扩张和气液掺混同时进行的动态发展过程;在通气云空泡的作用下,流体速度梯度是云空泡影响涡量输运的主要作用因素.
To study the flow characteristics of the ventilated cloud cavitation under vertical emission conditions,an Im-proved Delayed Detached Eddy Simulation(IDDES)model is used to conduct non-constant numerical simulations with the underwater vehicle as the research object.The introduction of hybrid scale accelerates the Reynolds Average Navier-Stokes(RANS)to Large Eddy Simulation(LES)conversion calculation and improves the calculation accuracy of turbulent stresses.A vertically constrained underwater launch platform was built,and the development process of ven-tilated cloud cavitation was studied using the quantitative exhaust method,while the validity of the numerical method was verified.It was found that the gas-liquid interface was destabilized under the action of vortex flow.After that,part of the water phase converged through the gas-liquid interface into the ventilated cavitation,and gas-liquid mixing oc-curred to form cloud cavitation.The evolution of cloud cavitation is a dynamic development process,where size ex-pansion and gas-liquid admixture are simultaneous.