Wake flows have significant effects on vehicles, buildings, and other objects encountered in daily life.Thus, wake control techniques are of practical importance and have been extensively investigated.One passive wake-control technique is to create a vent on a bluff body, which has been determined to be CD Cabinet effective for wake control on a circular cylinder but has not been sufficiently studied for wake control on a sphere.
Therefore, this study examined the effect of the vent angle on the characteristics of the wake of a sphere.A sphere with a uniaxial through-hole (vent) was placed in a uniform flow, and the vent angle was varied in the streamwise direction.The Strouhal number in the high-frequency and low-frequency modes was examined.
The flow field in the sphere wake varied with respect to the vent Speciality Boxes angle.Three frequency modes (high, low, and very low), the occurrence of a switching phenomenon, wherein the velocity fluctuated between positive and negative values, and high-frequency energy injection by the vent were observed.In addition, a high dominant frequency was observed only in the positive velocity fluctuation region.