小尺度矩形截面风洞的壁湍流流场测试

Exploring Feasibility of a Small-scale Wind Tunnel with Rectangular Section Suitable for Experiments on Wall Turbulent Flow

通过对小尺度矩形截面风洞内时均速度、湍流度、湍动能等湍流特性的测试,研究了基于该类风洞开展壁湍流相关技术试验的可行性,并以沟槽表面流场为例进行了测试验证。该风洞试验段截面尺寸为400mm×100mm,试验中瞬时流速的测量采用配置单直丝探针的IFA300恒温式智能型热线风速仪。试验数据处理时,壁面摩擦速度的计算采用基于对数律公式的拟和计算方法。测试结果表明,该小尺度风洞在较低风速下即可实现充分发展的湍流流动,且不同风速下试验段内湍流特性均与充分发展壁湍流边界层基本一致,可方便地应用于特种表面减阻等壁湍流相关技术的试验研究。

Having carried out lots of experiments about turbulent flow, such as turbulence intensity, turbulence kinetic energy, skewness factor and flatness factor in a small-scale wind tunnel with rectangular cross-section,this paper analyzes the feasibility of wall turbulent flow test using a small-scale wind tunnel with rectangular section. Then the turbulent flow over riblets surfaces is carried to verify accuracy. The size of the rectangular cross-section is 400 minX 100 mm. The flow field is tested by a TSI-IFA300 hot wire anemometer. In the calculating of the wall friction velocity, a method with least-squares fitting method is presented, which is based on the flow velocity distribution formula of logarithmic region in the turbulent boundary layer. Ultimate results show that the turbulent flow appears in a lower wind speed in this wind tunnel, and the turbulent flow characteristics in the small-scale wind funnel are alike with a wall turbulent boundary layer, so the flow field in a small-scale wind tunnel with rectangular cross-section is able to be used to carrying out wall turbulent flow characteristic tests, such as turbulent boundary layers over riblets surface.