迎角变化对细长旋成体绕流非定常压力脉动特征的影响

The impact of variant attack of angle on the unsteady pressure fluctuation characteristics of the flow over slender body

在亚临界流动范围内,通过对尖拱细长旋成体在无侧滑状态下的烟线显示和脉动压力测量试验,揭示了迎角α从0°向90°变化过程中细长体绕流依次经历了四种背涡流动结构:附着流动、对称二涡结构、非对称多涡结构和混合背涡结构。压力的脉动幅度在附着流动和对称二涡结构中沿轴向基本保持不变,在非对称多涡结构中是沿轴向增长的,而在混合背涡结构中却变为沿轴向减少。压力脉动频率值在非对称多涡结构中是沿轴向减少的,而在混合背涡结构中却是沿轴向增长的。

Tests of sharp ogive nose cylinders at variant angle of attack with smoke visualization and pressure fluctuation measurement have been carried out in subcritical Reynolds number region. As the angle of attack α increasing from 0° to 90°, there are four kinds of vortices structure and they are attaching flow structure.twin vortices structure.asymmetric vortices structure and mixed vortices structure in turn. The pressure fluctuation magnitude alone the axis is unchanged in attaching flow structure and twin vortices structure, increasing in asymmetric vortices structure, and decreasing in mixed vortices structure. The pressure fluctuation frequency alone the axis is decreasing in asymmetric vortices structure, and increasing in mixed vortices structure.