陷落腔跨度对剪切层自持振荡特性的影响

Influence of span of cave in cavity on self-sustained oscillations at shear layer

针对均匀流场中不同跨度的三维陷落腔因流分离而产生的剪切层自持振荡问题,开展了系列实验研究。在来流为0°攻角,Re=2.06×10-5～1.16×10-6时分析了腔体跨度变化对三维陷落腔剪切层自持振荡特性的影响。实验中测量了三维腔体剪切层处腔体侧壁的周向流体压力,分析了腔口剪切层处流体压力的分布规律及其自持振荡特性。实验结果表明:均匀流作用下,腔体跨度的增大使剪切层处稳态压力系数Cp增大,使剪切层随边处Cp′增大,但腔体跨度的增加会使剪切层自持振荡频率明显降低。

Aimed at the problem of self-sustaining oscillation at sheer layer induced by fluid separation in 3D cave-in cavity with different span in uniform flow field,a series of experiments were carried out. The influence of span change on self-sustaining oscillation characteristics of shear layer of 3D cave-in cavity was analyzed at 0° attack angle,Where Re =2.06×10^-5～1.16 ×10^-6. Circumferential fluid pressure at shear layer of 3D cave-in cavity is measured. Distribution rule of fluid pressure and self-sustaining oscillation characteristics of shear layer were analyzed. The results of experiment show that the increase of span of cave-in cavity will result in increase of steady state pressure coefficient at shear layer Cp, at the same time, it will bring the promotion of trailing edge of shear layer C＇p. But the increase of span of cave-in cavity can induce the drop of self-sustaining oscillation frequency at shear layer.