Passive control on wake structure of a wall-mounted cube by using a horizontal hole

• Published in: Ocean engineering 2020-10, Vol.213, p.107680, Article 107680
• Main Authors: Li, Jiawei, Rinoshika, Hiroka, Rinoshika, Akira
• Format: Article
• Language: English
• Subjects: Passive flow control; PIV; POD; Vortex dynamics; Wake; Wall-mounted cube
• ISSN: 0029-8018; 1873-5258
• DOI: 10.1016/j.oceaneng.2020.107680

To control the wake flow around a wall-mounted cube, a passive control method is proposed by drilling a horizontal hole from the front surface to rear surfaces of the cube. The controlled and uncontrolled wakes are measured by using particle image velocimetry (PIV). The cube model has a side length of D = 70 mm, and the diameter of horizontal control hole (HCH) is d = 10 mm. Reynolds number based on side length of cube is ReD=11,550. Furthermore, to study the positional effect of the HCH, three kinds of holes with different heights h are used. The time-averaged statistical characteristics show that the jet generated from the HCH reduces the scale of the arch-type vortex, turbulence intensity, Reynolds shear stress and turbulent kinetic energy in the wake, and enhances the recovery of streamwise velocity. Among three HCHs, the HCH of h = 35 mm has the optimal control effectiveness. The analysis of vortex dynamics indicates that the HCH jet effectively suppresses the periodic flow structures and accelerates the wake vortex shedding. Meanwhile, the HCH jet exhibits different effect on the spanwise vortex at its different heights. The POD analysis implies that under the influence of the HCH, the alternant spanwise vortices are suppressed, but symmetric vortices are relatively enhanced. •>A passive flow control method using a horizontal hole is proposed.•The scale of the arch-type vortex was reduced.•Reynolds shear stresses and turbulent kinetic energy were reduced.•The symmetric vortices were relatively enhanced.•The periodic structure and the wake vortex shedding were effectively suppressed.