Characteristics of unsteady turbulent boundary layr with separated vortices

研究了具有分离涡的非定常湍流边界层特性。对三种流场进行了实验测量。薄边界层中大粗糙度后的流动。以波的形式绕着圆柱体流动。结果表明：1.当粗糙度面密度超过圆柱体表面的15%时，粗糙度接近参考直径的圆柱体的有效直径DR=D+2K(D：圆柱体直径，K：粗糙度高度)。在波面下方布置一个平行于波峰的圆柱体时，可以观察到旋转流动。分析的惯性力和粘性力在波动和振荡运动中表现出不同的特性，但无因次系数的取值几乎相同。在低频谐波下，三维纵向涡的变化与精细船模尾迹分布之间存在一定的相关性。较强的纵向涡使得全船型船型后的尾迹分布稳定。

Characteristics of unsteady turbulent boundary layr with separated vortices were investigated. Three kinds of flow field were measured experimentally.1. Flow behind large roughness in thin boundary layr.2. Flow around a circular cylinder in waves.3. Flow behind two kinds of ship stern, fine ship model and full ship model.Obtained results are as follows ;1. When the area density of roughness exceed 15% of surface of a cylinder effective diameter of the cylinder with roughness close to the reference diameter Dr=D+2K (D : diameter of cylinder, K : roughness height).2. Roating flow are observed when a circular cylinder was arranged under the wave surface and settled parallel to the crest line.3. Analyzed inertia force and viscous force show different characteristics in wave or oscillating motions, but non-dimensional coefficients are almost the same values.4. There are some correlation between variation of 3-d longitudinal vortices and wake distributions of fine ship model at low frequency harmonics.5. Stronger longitudinal vortices make the wake distribution behind a full hull form model ship stable.