仿生射流表面流场控制减阻数值模拟  

Simulation on Flow Control and Drag Reduction with Bionic Jet Surface

作　　者：李芳[1] 赵刚[1] 刘维新[1] 孙壮志[1] 

机构地区：[1]哈尔滨工程大学机电工程学院,黑龙江哈尔滨150001

出　　处：《应用基础与工程科学学报》2014年第3期574-583,共10页Journal of Basic Science and Engineering

基　　金：国家自然科学基金项目(51275102)

摘　　要：利用SST k-ω湍流模型对仿生矩形射流表面的减阻特性进行数值模拟,解释了射流表面减小摩擦阻力的原因及对近壁区边界层的控制行为.结果表明,射流孔面积相等时,射流孔与射流表面沿展向长度的比值越大,减阻效果越好.当其它因素不变时,随着射流速度的增大减阻率逐渐增大,随着射流流量的增大减阻率逐渐增大,最大减阻率为35.97%.射流表面对边界层的控制行为表现为主流场近壁区的剪切流动遇到射流的阻抗,在射流孔的背流面形成逆流区,逆流在边界层底层产生的剪应力与主流场方向相反;同时在射流孔下游产生反向旋转涡对并在近壁面诱导出二次涡,相当于在高速流体与壁面之间产生润滑带,使边界层黏性底层厚度增大,速度梯度减小,摩擦阻力减小.Numerical simulations of drag reduction for the rectangular bionic jet surface were carried out with SST κ-ε turbulence model. The paper analyzed the reasons of drag reduction of the jet surface and demonstrated the control behaviors for the boundary layer near wall region. The results show that, in condition of jet holes with equal area, the greater the ratio between jet hole and span-wise length on jet surface is, the better the performance of drag reduction is. When other factors are not changed, the drag reduction efficiency is increased gradually as the jet velocity is increased and jet flow is accrued respectively, up to 35.97%. The control behavior of the jet surface for the boundary layer appears as jet impedance occurred in sheer-flow of the near wall region in cross flow, which develops reverse-flow zone in the lee side of jet surface. And the direction of sheer stress produced by the reverse-flow in the viscous sublayer of boundary layer is opposite to the direction of cross flow. Meanwhile, it would produce counter- rotating vortices in the downstream of jet hole and induce secondary vortices near wall region. The effect is counterpart of lubrication belt between the fluid with high speed and the wall. As a result,it increases the thickness of the viscous sublayer and decreases the velocity gradient and friction resistance.

关 键 词：仿生射流表面 减阻 数值模拟 边界层 

分 类 号：TB17[生物学—生物工程]