风洞模型-支撑系统涡激振动测量与分析

以0.55m×0.4m低湍流航空声学风洞某模型及其支撑系统为研究对象,采用基于加速度传感器直接测量支撑系统和热线间接测量模型尾流相结合的方法,测量并分析了风洞模型-支撑系统的涡激振动模态,给出了测量方案和数据处理方法。采用基于加速度传感器的功率谱分析方法,获得了模型-支撑系统的三阶振动频率分别为31.1、120.9和221.4Hz;采用基于加速度传感器的频域滤波和频域积分方法,提高了有效信号的信噪比,获得了模型-支撑系统振动的振型和振动节点位置;采用热线测量模型尾流分离涡脱落频率的方法,获得了模型一阶和二阶振动的尾流涡激频率分别为31.1和124.1 Hz,并从测量尾流速度脉动量获得了模型振幅变化和抖振边界信息。实验结果表明,采用热线测量模型尾流从而分析模型振动的方法,有利于小尺度的模型振动测量,而且相对于加速度传感器装于模型表面的直接测量方法而言,对试验模型的绕流流场干扰较小,为测量风洞试验模型的涡激振动模态提供了一种方法。

Vortex-induced vibration measurement and analysis of model-sting system in wind tunnel

Long cantilever stings that support aerodynamic models in wind tunnels are a po-tential source of vibration problems which would impair the test data quality.It is reported in many documents to use the method of setting sensors on models to measure vibrations of the model-sting system,but setting sensors on small models is hard to realize.In this paper,a 0.55m×0.4m low turbulence aeroacoustic wind tunnel model-sting system is employed as the experimental object, acceleration sensors which directly measure the equipmentvibration and hot wires which indirectly measure the model wake are made use of jointly.The vortex-induced vibration models of the sys-tem are measured and analyzed.Wake measurement by hot wire to acquire vibration parameters of the model is tried,and this method is easy to be emploied for small models.At the same time, the methods of accelerator signal frequency domain filtering and frequency domain integration is used to acquire vibration model parameters of the model-sting for purpose of comparison with da-ta of hot wire.This method could improve the SNR of effective signal.With the method of accel-eration sensors power spectrum analysis,three order vibration frequencies of 31.1,120.9 and 221.4Hz of the system are acquired.With the method of frequency domain filtering and frequen-cy domain integration,the vibration mode and node of the system are acquired.With the method of hot wire measuring wake,vortex shedding frequencies of 31.1 and 124.1Hz,and the model buffet boundary are acquired.Experimental results show that,the results show that,the method of hot wire measuring model wake vortex shedding frequency for the analysis of aircraft model vi-bration is propitious to be applied for small models,since it has less interference with model sur-face flow field than the method of setting sensors on model surfaces.Therefore,the hot wire method is a practical method for vortex-induced vibration measurement.