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高速开式空腔流动,腔内存在较复杂的流场结构,在一定条件下腔内存在较为严重的压力、速度等脉动,诱发强烈噪声,声压级(SPL)甚至可高达170dB,对腔内的储藏物与空腔自身结构安全构成较大威胁,因此开式空腔噪声抑制方法成为争相研究的热点。为此,对跨、超声速流动条件(马赫数Ma=0.9,1.5)下有、无零质量射流时开式空腔(长深比L/D=6)气动声学特性进行了较详细地分析,并通过综合对比分析空腔底面中心线上的声压级分布和不同测点的声压频谱(SPFS)特性,探讨了不同零质量射流方式对空腔气动噪声的抑制效果。研究结果表明,跨声速(Ma=0.9)条件下,采用的零质量射流对空腔内噪声有一定抑制效果,使得空腔前部区域声压级降低幅度比后部区域大,射流出口位于腔前壁上(射流方向平行来流)的射流方式对腔内噪声抑制效果要比射流出口位于腔前壁前(射流方向垂直来流)的射流方式好;超声速(Ma=1.5)条件下,采用的零质量射流对空腔内气动声学特性影响很小,对腔内噪声几乎无抑制效果。
High-speed open cavity flows, there are complex flow field structure in the cavity, under certain conditions there are more severe pressure, velocity and other pulsations, inducing strong noise, the sound pressure level (SPL) even up to 170dB, the cavity The storage in the cavity poses a big threat to the structural safety of the cavity itself. Therefore, the open-cavity noise suppression method has become a hot spot competing for research. Therefore, the aerodynamic characteristics of the open cavity (L / D = 6) with and without zero-mass jet under cross-supersonic flow conditions (Mach number Ma = 0.9,1.5) are analyzed in detail. The effects of different zero mass jet modes on aerodynamic noise suppression were discussed by comprehensively analyzing the sound pressure level distribution on the centerline of the cavity bottom surface and the sound pressure spectrum (SPFS) of different measuring points. The results show that the zero-mass jet with a certain speed of sound (Ma = 0.9) can restrain the noise in the cavity to some extent, so that the sound pressure level in the front of the cavity decreases more than that in the back and the jet outlet is located in the cavity The jet mode on the anterior wall (jet flow parallel to the jet flow direction) is better for the suppression of intracavity noise than the Jet jet jet flow in front of the anterior wall of the jet chamber (perpendicular jet flow direction); under the supersonic speed (Ma = 1.5) Of the zero-mass jet has little effect on the aerodynamic acoustical characteristics of the cavity and has almost no inhibitory effect on the cavity noise.