基于MEMS传感器的高速风洞壁面剪切应力直接测量技术

提出了一种新的壁面剪切应力测量方法,使用锯齿状排布的MEMS传感器作为敏感元件,在高速风洞中对研制的剪切应力测量设备进行了原理验证实验.实验结果显示湍流中的局部壁面剪切应力大小是层流中的两倍以上,监测局部剪切应力可以作为一种有效的边界层转捩的实验判定方法.利用这一方法测得的转捩区与使用脉动压力测试技术测得结果一致,验证了通过MEMS元件监测局部剪切应力作为边界层转捩测量手段的可行性和可靠性.

Direct measurement technique of wall shear stress using MEMS sensors in a high-speed wind tunnel

This paper presents a direct measurement technique for wall shear stress.The capacitive MEMS sensor with pectinate floating element was developed.The techniques of static and dynamic calibration are introduced.The demonstrative experiment was carried outina high-speed wind tunnel.The experiment results indicate that the local shear stress in turbulent flowis noticeably higher than in laminar flow.Monitoring local shear stress on a model can be also used for determining transition zone.In the present experiment,the transition zone detected by the MEMS sensor is identical with what by the pressure transducer.