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采用大涡模拟方法数值研究了来流马赫数为0.75、雷诺数为2×105的带挡板圆柱可压缩绕流.由于带挡板圆柱绕流的被动控制,与圆柱相比,带挡板圆柱的阻力减小了33%,升力系数的振荡几乎被完全抑制.在此类流动中,由剪切效应引起的减阻大于可压缩效应的影响.通过分析挡板的被动控制机理,我们发现抑制剪切层的失稳可以提高柱体的背压,这与柱体减阻和升力系数振荡抑制密切相关.通过分析沿剪切层的对流马赫数和自激振荡现象,发现在可压缩效应和高频力效应共同作用下,带挡板圆柱的剪切层失稳得到了抑制.
A large eddy simulation method was used to numerically study compressible compressible circular flow with a baffle cylinder with a flow Mach number of 0.75 and a Reynolds number of 2 × 105. Due to the passive control of flow around the baffle cylinder, The resistance of the cylinder is reduced by 33% and the oscillation of the lift coefficient is almost completely suppressed.In this kind of flow, the drag reduction caused by the shearing effect is larger than that of the compressible effect.By analyzing the passive control mechanism of the baffle, we find that Suppressing the instability of the shear layer can increase the backpressure of the column, which is closely related to the cylinder drag reduction and the suppression of the lift coefficient oscillation.By analyzing the convection Mach number and the self-oscillating phenomenon along the shear layer, we find that in the compressible effect In combination with the high-frequency force effect, the instability of the shear layer with baffled cylinder is suppressed.