3/4开口式汽车风洞驻室内流场速度脉动的研究

摘要

The present study is an assessment of velocity fluctuations in a 3/4 open-jet type wind tunnel using both CFD and test methods.A virtual wind tunnel was created out of the plenum of the 1:15 scaled wind tunnel.Simulations were first carried out for the flow inside the plenum of the scaled wind tunne l using the URANS.The inlet boundary condition was defined as the combination of a constant mean velocity and an oscillating component.Both the oscillating frequencies and the mean velocities were varied in the simulations.Test for the same scale wind tunnel was carried out.Both the test and the simulation lead to the same results,showing that the unsteady flow grows in the plenum in the flow direction and the leading oscillation has a frequency of 20Hz.%采用数值和实验相结合的方法,对3/4开口回流式风洞驻室内的速度脉动进行了研究.首先搭建了1:15的模型风洞驻室的数值模型.对此模型风洞驻室内的流场采用非定常的雷诺时均方法进行了数值模拟.λ口边界速度条件由不变的平均速度量和带有周期性扰动的速度变量线性组合构成,其中计算了扰动量具有不同频率和平均速度设为不同常量的工况.同时在此模型风洞内对驻室内流场进行了相应工况的实验测试,实验和计算结果吻合度很好,得到结论是非定常流态在风洞驻室内随流动的发展而发展,并且引起了频率为20Hz的扰动.