壁面微结构流动控制技术的减阻机理研究

为了研究壁面微结构流动控制技术的减阻效应及其产生的原因,利用循环管路系统的方形管道进行了压降测定试验,并利用粒子成像测速仪测量了边界层内部结构和对应的参数。试验采用了沟槽和肋条两种不同类型的微结构壁面,每种形状的微结构各有3种不同的结构尺寸。试验研究结果表明:在一定的无量纲宽度s+范围内,6种不同的微结构壁面都具有减阻效果;减阻率随着s+的增大,呈现先增大后减小的趋势,其中沟槽壁面2的减阻效果最好,最大减阻率为9.90%;壁面微结构通过影响流场内部的涡结构、湍流脉动、雷诺切应力和平均流速等使得不同壁面微结构具有减阻效果。

On the mechanism of drag reduction of wall microstructure flow control technique

In the present work drag reduction and its causes of wall microstructure flow control technique have been investigated experimentally.Pressure drop tests were carried out on a closed rectangular duct and particle image velocimetry was used to measure inner structure and corresponding flow parameters of boundary layer.Plates with micro-grooves or micro-riblets were fixed as the floor of the duck pipe.The result shows that a notable decrease in drag reduction for microstructure surfaces can be seen at a certain range of s⁺.The dag reduction rate increased first then decreased with the increase of s⁺,and a maximum rag-reduction of nearly 9.9 percent was acquired over the micro-grooves surface B.Microstructure can thicken the boundary layer and weaken turbulent fluctuation intensity.What''s more,Reynolds shear stress,and root-mean-square velocity both decreased.