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.