01. Experimental/Computational Fluid Dynamics

Jet flow technology has been applied to stall control in wings. Additionally, research has been conducted on circulation control wings (CCW), which use a jet sheet to control lift as an alternative to flaps. CCW is a high-lift device that generates circulation around the wing because of the Coanda effect by blowing a jet sheet tangentially on the negative pressure side of the wing. However, previous studies focused on lift characteristics, and there is insufficient information applying tangential blowout (jet sheet) for directional control of the generated flow. Although multiple-slots with film cooling are effective for the application of tangential blowouts for directional control of hot jets, the information on the influence of the number of blowout slots on the deflection characteristics of the flow is inadequate. In this study, we attempted to reveal the flow around a double-slot tangential-blowout cylinder for controlling the flow direction using a tangential-blowout cylinder with multiple slots. First, we discuss the similarities and differences in the flow characteristics between single-slot and double-slot jets. The momentum coefficient Cμ, which represents the momentum ratio between the main jet and jet sheet, and slot installation angle θj were selected as the main parameters, and the jet deflection characteristics were investigated based on the time-averaged velocity distribution and visual observation using a hot-wire anemometer. In this experiment, the Reynolds number based on the cylinder diameter and the mainstream velocity was set to Re = 2.7 × 10^4 , with the cylinder diameter fixed at 50 mm and the mainstream velocity fixed at 8.3 m/s. According to the results, the single-slot and double-slot jets show different deflection characteristics for the same momentum coefficient Cμ, and the oscillatory characteristics of the backward flow depend on the slot installation angle θj.