Numerical Analysis of the Effects of Periodic Gust Flow on the Wake Structure of Ventilated Supercavities

Abstract

A computational model is established to investigate the effects of a periodic gust flow on the wake structure of ventilated supercavities. The effectiveness of the computational model is validated by comparing with available experimental data. Benefited from this numerical model, the vertical velocity characteristics in the entire flow field can be easily monitored and analyzed under the action of a gust generator; further, the unsteady evolution of the flow parameters of the closed region of the supercavity can be captured in any location. To avoid the adverse effects of mounting struts in the experiments and to obtain more realistic results, the wake structure of a ventilated supercavity without mounting struts is investigated. Unsteady changes in the wake morphology and vorticity distribution pattern of the ventilated supercavity are determined. The results demonstrate that the periodic swing of the gust generator can generate a gust flow and, therefore, generate a periodic variation of the ventilated cavitation number σ. At the peak σ, a re-entrant jet closure appears in the wake of the ventilated supercavity. At the valley σ, a twin-vortex closure appears in the wake of the ventilated supercavity. For the forward facing model, the twin vortex appears as a pair of centrally rolled-up vortices, due to the closure of vortex is affected by the structure. For the backward facing model, however, the twin vortex appears alternately as a pair of centrally rolled-up vortices and a pair of centrally rolled-down vortices, against the periodic gust flow.

Influence of Periodic Disturbance Incoming Flow on the Supercavitation Phenomenon

“…Yang et al studied the effect of heating a hydrofoil surface on cavitation and found that transient cavitation occurs on the surface of the heated hydrofoil, and with the increase in temperature, the transient cavitation will become open-type cavitation . Wang et al studied the influence of periodic gust flow on the cavitation shape at the tail of ventilated supercavitation . Zhan et al studied the influence of lateral flow on supercavitation and concluded that the cavity morphology is symmetrical in the absence of lateral flow and asymmetrical in the presence of lateral flow, with the cavity morphology increasing with the velocity .…”

“… 16 Wang et al studied the influence of periodic gust flow on the cavitation shape at the tail of ventilated supercavitation. 17 Zhan et al studied the influence of lateral flow on supercavitation and concluded that the cavity morphology is symmetrical in the absence of lateral flow and asymmetrical in the presence of lateral flow, with the cavity morphology increasing with the velocity. 18 Fan et al studied the change in supercavitation when the projectile passes through different density regions and found that the diameter contraction of the projectile occurs through different density regions and in different locations and is related to the density degree.…”

Experimental and Numerical Research on the Formation Conditions and Entrainment Characteristics of Supercavity by Rear Jet Reflux

“…Besides, other flow characteristics had also been studied through numerical simulation methods. Wang et al (2021) established a computational model to investigate the effects of a periodic gust flow on the wake structure of ventilated supercavity. The conclusions demonstrated that the behavior of ventilated supercavity against unsteady incoming flow was more stable than the vapor cavity.…”