平底气泡船凹槽气层波动特性

为提高大型平底气泡船底部凹槽设计的有效性,基于RANS方程及VOF两相流模型构建了大型平板船凹槽气层数值计算模型。研究气层在凹槽中的动态发展过程,分析速度对气层波动的影响规律,并阐述三维凹槽气层的波形特性及其与二维气层波动的区别,揭示气层波动的相似律。数值结果表明:气层在凹槽中呈现波动形态,气层波长随速度的增加而增大,波长等于速度平方的0.64倍;气层在凹槽侧壁的干扰及反射下呈现相干波系,从而其波高及局部厚度也随之改变;气层波动满足傅汝德相似。

Characteristics of air layer fluctuations on flat bottom air cavity ship with groove

In order to improve the design effectiveness of large flat bottom ship with groove, a calculation method with combination of RANS equations and VOF two-phase-flow model is proposed for a large flat bottom ship with groove. The dynamic development of air layer in the groove was found. Based on the analysis of air layer fluctuations with different flow velocity, the difference of air layer fluctuations characteristic between three-dimensional and two-dimensional is explained and the fluctuations similar-law of air layer is obtained. Numerical results show that air layer appear fluctuations in the groove and the wavelength of air layer increases with increasing of velocity; the wavelength is equal to 0.64 times of the square of velocity; Air layer presents phenomenon of coherent and reflection at the side walls of groove, so the wave height and thickness of local air layer were changed; Fluctuations of air layer is satisfy with Froude similar.