Active wake control of a bluff body with blunt trailing edge using incompressible numerical simulations

Abstract

The flow over a bluff body with a blunt trailing edge has been extensively studied due to its relevance in underwater vehicles, such as submarines and torpedoes, where wake control is critical for optimizing stealth and reducing detectability. However, the specific effects of jet blowing and suction at the rear of D-shaped bluff bodies on wake dynamics have not been adequately explored. Four configurations—balanced inversion (BI), opposite injection–suction (OIS), interleaved injection–suction (IIS), and double injection–double suction (DIDS)—were examined, each with five velocity ratios (0.5, 1, 1.5, 2, 2.5) where the velocity ratio (u/u∞) is the ratio of freestream velocity to injection/suction velocity with slits evenly spaced along the rear end of the bluff body. The results revealed that the BI configuration, with symmetric suction and injection, effectively stabilized the wake and reduced drag by 26% at an optimal velocity ratio of u/u∞ = 1.5. Conversely, higher velocity ratios led to the reemergence of vortex shedding and increased drag. The OIS configuration demonstrated a complex interplay of vortex interactions, particularly at higher velocity ratios, resulting in a substantial rise in drag (up to 101.38% at u/u∞ = 2.5). The IIS configuration yielded more predictable vortex patterns and reduced drag at lower velocity ratios, although chaotic flow reemerged at higher ratios. The DIDS configuration significantly altered wake dynamics, deflecting vortices, narrowing the wake, and increasing drag at higher velocity ratios, with a notable shift in vortex shedding frequency. These findings contribute to understanding wake control techniques, offering potential benefits for the design of stealthier underwater vehicles.