近自由面串列超空泡航行体的流动特性研究

Study on the flow characteristics of tandem supercavitating vehicles nearthefreesurface

近自由面串列超空泡航行体的多相流动现象非常复杂,涉及了自由面与空泡的耦合作用以及2个甚至多个超空泡流场的相互干扰.采用VOF方法数值模拟了不同浸没深度条件下串列航行体的多相流动,获得了串列航行体的超空泡演化特性和流场分布特性,分析了自由面对超空泡形态及波浪特征高度的影响.研究结果表明:串列双航行体的超空泡在发展过程中出现了2个超空泡互相融合与分离、尾空泡溃灭等现象;超空泡流场的彼此相互作用导致后发航行体进入了前发航行体的超空泡内部,导致后发航行体受到的阻力减小,航行体的串列布置使后发航行体实现了减阻效果;浸没深度较小时,自由面的作用明显,航行体的超空泡形态上下对称性较差,自由面兴起的波浪特征高度较大,前端高压区压力分布沿航行体中心线不对称.

The multiphase flow characteristics of tandem supercavitating vehicles near the free surface are very complex.They not only involve the coupling effect of the free surface and the cavitation,but also the mutual interference of two or more supercavitating flow fields.This paper uses the VOF method to simulate the multiphase flow of tandem vehicles under different immersion depths.It also obtains the supercavitation evolution characteristics and flow field distribution characteristics of the tandem vehicles,and analyzes the effects of the free surface on supercavity shape and wave characteristic height.The results show that the supercavitation of the tandem bi-vehicles appears the phenomena of fusion and separation of the two supercavities and collapse of the tail bubbles during the development process.The interaction of the supercavitation flow field causes the second vehicle to enter the interior supercavity of the first vehicle,