汽车天窗开槽扰流器的降噪机理试验研究

Experimental Research on Noise Reduction Mechanism of a Groove Spoiler in Vehicle Sunroof

开槽扰流器能有效地降低汽车天窗开启的风振噪声.为了更好地理解其降噪机理,构建了开槽扰流器和平直扰流器风洞试验平台,通过风洞试验来调查扰流器有无开槽对其后方壁面压力场的影响.试验结果表明,相比于平直扰流器,扰流器的开槽能够将流动再附着点提前,减少了气流的再循环区域,开槽扰流器下游流动存在初始的展向相位差,降低了壁面压力展向上的相干性,导致壁面压力在展向上具有较大的衰退性.因此开槽扰流器,对下游流动的扰动效果非常明显,能够弱化对乘员舱的激励.

A groove spoiler can effectively reduce vehicle sunroof buffeting noise.In order to have a better understanding of sunroof buffeting noise reduction mechanism associated with groove spoilers,a test platform of groove and uniform spoiler was built.Wind tunnel experiments were performed to investigate the surface pressure field downstream of uniform and grooved spoilers and to observe the effects of the grooves on the wall pressure.The test results show that the presence of grooves in the spoiler moves the reattachment point upstream and reduces the recirculation region length.Compared with the uniform spoiler,an initial spanwise phase difference was observed behind the spoiler in the presence of the groove,which decreased the coherence of the wall pressure,and the wall pressure had a big decay rate in the spanwise direction.Grooves in the spoiler can obviously disturb the downstream flow,and thus it can weaken the primary aerodynamic excitation for the vehicle cabin.