Abstract
Abstract
The vortex-ring interaction of synchronous jets has been paid more attention by predecessors, while the research of asynchronous jets (i.e. there is a time difference between the start of jets) of parallel dual nozzles has been studied less. Therefore, the interaction between vortex rings and the vortex structure evolution of the dual-nozzle asynchronous jets with different time differences (Δt) is studied in this paper. Numerical results obtained can be divided into four intervals: 1. Synchronous jets (Δt = 0); 2. Critical interval (Δt < 0.1t, where t is the jet time), having similar vortex structure evolution modes and dynamic characteristics as the synchronous jet; 3. Strong interaction interval (0.2t ≤ Δt ≤ 0.4t), in which the main vortex ring shows obvious acceleration, and the streamwise vortex structure is found in the wake; 4. weak interaction interval (Δt ≥ 0.6t), in which the interaction between vortex rings is much less strong and the streamwise vortex structure also appears in the wake. In addition, it is found that pressure on the nozzle outlet plane increases and the vortex dissipation in the downstream flow field slows down significantly due to the vortex-ring interaction on the condition of asynchronous jets.
Subject
Computer Science Applications,History,Education
Reference16 articles.
1. Mechanism of underwater biological jet propulsion and application in bionic water jet propulsion vehicle [J];Wang;Robot,2009
2. Passive energy recapture in jellyfish contributes to propulsive advantage over other metazoans [J];Gemmell;Proc. Natl Acad. Sci,2013
3. Effects of multijet coupling on propulsive performance in underwater pulsed jets [J];Athanassiadis;Physical Review Fluids,2016
4. A universal time scale for vortex ring formation [J];Gharib;Journal of Fluid Mechanics,1998
5. The formation of vortex tings [J];Glezer;Physics of Fluids,1988