水下平板通气减阻特性研究
Drag reduction characteristics of an underwater air lubrication flat plate
余恒安 1张焕好 2陈志华 2郑纯 2彭江舟2
作者信息
- 1. 北京动力机械研究所,北京 100074;南京理工大学 瞬态物理国家重点实验室,江苏 南京 210094
- 2. 南京理工大学 瞬态物理国家重点实验室,江苏 南京 210094
- 折叠
摘要
为了研究通气射流对水下平板阻力特性的影响,本文采用Mixture多相流模型和Realizable k-ε湍流模型研究了三维水下平板通气射流的流动结构特征,得到了水下平板表面气液流场结构和减阻特性.数值结果表明:气体注入后,受来流影响而紧贴壁面向下游发展.当气体稳定覆盖在平板壁面后,平板阻力系数较不通气情况降低了 16.73%.另外,因气体注入壁面边界层后,提升了壁面上的速度梯度,降低了壁面流体粘性系数;在气膜覆盖区(αl>80%),因流体粘性系数的下降量远大于速度梯度的上升量,使流体粘性系数对气膜核心区内的减阻率起决定性作用;对于远离气膜核心区外的壁面,切向速度梯度对摩擦阻力系数的贡献增强.
Abstract
To study the effect of ventilation jets on the resistance characteristics of underwater flat plates,the mix-ture multiphase flow model and Realizable k-ε turbulence model investigated the flow feather of a three-dimensional underwater flat vented jet,obtaining the structure and drag reduction characteristics of the gas-liquid flow field on the underwater flat surface.Numerical results showed that after the gas was injected,it was affected by the incom-ing flow and developed downstream closely along the wall.When the gas stably covered the plate wall,the resist-ance coefficient of the plate was 16.73%lower than the unventilated case.Because of the injection of gas on the wall boundary layer,the wall velocity gradient was increased,and the wall fluid viscosity coefficient was reduced;in the gas film coverage area(αl>80%),because the decrease in the fluid viscosity coefficient was much greater than the increase in the velocity gradient,the fluid viscosity coefficient played a decisive role in the drag reduction rate in the core region of the gas film;for the wall far from the core area of the gas film,the contribution of the tan-gential velocity gradient to the friction resistance coefficient was enhanced.
关键词
通气射流/平板/减阻率/粘性系数/速度梯度/核心区/数值模拟/摩擦系数Key words
ventilation jet/flat plate/drag reduction rate/viscosity coefficient/velocity gradient/core area/nu-merical simulation/friction coefficient引用本文复制引用
基金项目
瞬态物理重点实验室项目(614260403041802)
出版年
2024
国家科技期刊平台
NSTL
万方数据