Water-entry and-exit of a horizontal circular cylinder

Greenhow, Martin

doi:10.1016/s0141-1187(88)80003-8

Cited by 87 publications

(50 citation statements)

References 6 publications

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“…Here (3) is the body boundary condition imposed on the moving plate; conditions (4) correspond to the kinematic and dynamic boundary conditions on the free surface; the far-field conditions (5) imply that the flow caused by the lifting plate decays at infinity; and the initial conditions (6) imply that initially the liquid is at rest and its upper boundary coincides with y = 0. The small parameter ε appears in these equations in such a way that the nonlinear terms can be neglected in the leading order as ε → 0, and the boundary conditions can be imposed at the initial liquid level, y = 0.…”

Section: Formulation Of the Problemmentioning

confidence: 99%

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Initial stage of plate lifting from a water surface

2015

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This study deals with the flow induced by a rigid flat plate of finite length, initially touching a horizontal water surface, when it starts to move upwards with constant acceleration. In the present model, negative hydrodynamic pressures on the lower (wetted) surface of the plate are allowed, and thus, the water follows the plate due to the resulting suction force. The acceleration of the plate and the plate length are such that gravity, surface tension and viscous effects can be neglected during the early stages of the motion. Under these assumptions, the initial two-dimensional, potential flow caused by the plate lifting is obtained by using the small-time expansion of the velocity potential. This small-time solution is not valid close to the plate edges, as it predicts there singular flow velocities and unbounded displacements of the water-free surface. It is shown that close to the plate edges the flow is nonlinear and self-similar to leading order. This nonlinear flow is computed by the boundary-element method combined with a time-marching scheme. The numerical time-dependent solution approaches the self-similar local solution with time.

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Section: Formulation Of the Problemmentioning

confidence: 99%

“…Greenhow [6] and Greenhow and Moyo [7] studied the exit of initially submerged bodies by numerical methods. Oliver [8] was concerned with the stability of the advancing liquid-solid contact line.…”

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confidence: 99%

Initial stage of plate lifting from a water surface

2015

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“…Since the analytical solution is not valid for water impact and entry, the computed results are compared to those of Lin (2007). The two dimensionless parameters describing water exit, sinking and impact of circular cylinder, adopted in the literature (Greenhow, 1988) are…”

Section: Validation Of the Developped Modelmentioning

confidence: 99%

“…Some of these solid bodies are of cylindrical shape and can be members of offshore structures and piplines which are near or penetrating the free surface. The major hydrodynamic events associated with the water impact of horizontal circular cylinder moving in a calm free surface are identified by early analyses of flow visualization experiments (Greenhow, 1988). Recently, the hydrodynamic force and velocity flow field corresponding to the water entry of two dimensional wedge sections with constant velocity and for different deadrise angles are measured (Tveitnes, Clarke and Varyani, 2008).…”

Section: Introductionmentioning

confidence: 99%

A Moving Grid Model for Simulation of Free Surface Behavior Induced by Horizontal Cylinders Exit and Entry

Mnasri

Hafsia

Omri

et al. 2010

Engineering Applications of Computational Fluid Mechanics

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ABSTRACT:Computationnal fluid dynamics (CFD) analysis is applied to investigate the two dimensional entry and exit of horizontal cylinders in calm water. Free surface interaction with the moving cylinders is modelled using the volume of fluid method (VOF) and the dynamic mesh technique (DMT) is adopted to follow the bodies motions. The developed model is validated by following series of numerical experiments conducted by the fixed grid model of Lin (2007), with a single moving horizontal cylinder in calm water moving with constant or variable velocity. The computed free surface profiles were in very good agreement with those of Lin (2007) for both cases of an immersed cylinder moving upward or downward. For the case of water impact and entry, numerical results showed that the splash jet is adequately simulated along with the associated impulsive forces and the high pressures reported by Lin (2007). Once validated, this model was applied to study the interaction between the free surface and the entry and exit of twin cylinders. Compared to the single cylinder cases, the two cylinders simulations results showed that their impacts were much more significant for the entry case where a large central jet was observed.

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“…Greenhow (1988) studied the water entry of a rigid circular cylinder by using a boundary element method based on Cauchy's theorem. The water entry of a rigid circular cylinder is studied by Zhu et al (2006) who used a CIP (Communicating Interacting Processes) method.…”

Section: Introductionmentioning

confidence: 99%