Study of water entry of circular cylinder by using analytical and numerical solutions

Ghadimi, Parviz; Dashtimanesh, Abbas; Djeddi, Reza

doi:10.1590/s1678-58782012000300001

Cited by 36 publications

(32 citation statements)

References 14 publications

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“…It is considered that the model passes through a transverse plane and the three dimensional problem can be reduced to a water entry of a solid body with wedge section, as shown in Figure 19. Dynamic pressure distribution over the wall of the wedge can be computed using analytical scheme, numerical methods [52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67] or experimental measurements [68][69][70][71][72][73][74]. Here, the Wagner solution [75] is used as in when the water has not drenched the chine.…”

Section: Longitudinal Force Distributionmentioning

confidence: 99%

Experimental Study of the Wedge Effects on the Performance of a Hard-chine Planing Craft in Calm Water

2018

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In this paper, effects of a wedge on the performance of planing craft in calm water are experimentally investigated. Experiments are carried out on three different cases distinguished by the wedge type. The model, built of fiberglass, is a prismatic planing hull with deadrise angle of 24 degrees. Towing tests are conducted at different Froude numbers ranging from 0.21 to 2.1. The total trim angle, resistance, rise up at the CG as well as stern and bow, keel wetted length, chine wetted length, stagnation angle, and the length of stagnation line are measured. They are used to study the effect of installing a wedge on the performance as well as the effect of height on the hydrodynamic characteristics. Based on the observations made, it is concluded that, when the wedge is applied to the hull, the risk of model exhibiting instability diminishes, while total trim angle largely decreases, keel wetted length is enlarged, wetted surface becomes thinner, CG rise up is lowered, and the resistance is reduced. Moreover, experimental measurements and theoretical 2D+T theory are combined to bring deeper insight about physics of the flow and pressure distribution when a wedge is installed on the bottom of a planing hull.

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Section: Longitudinal Force Distributionmentioning

confidence: 99%

Experimental Study of the Wedge Effects on the Performance of a Hard-chine Planing Craft in Calm Water

2018

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“…Aristoff and Bush [15] presented the results of a combined experimental and theoretical investigation of the normal impact of hydrophobic spheres on a water surface by determining the shape of the air cavity behind the sphere, pinch-off time, and depth. Ghadimi et al [16] employed an analytical method and a numerical solution to study the water entry problem of a circular section. They demonstrated a procedure for the step by step derivation of the analytical formulas and presented a comparison between the linear and nonlinear solutions.…”

Section: Experimental Studiesmentioning

confidence: 99%

Numerical Investigation of Water Entry Problem of Pounders with Different Geometric Shapes and Drop Heights for Dynamic Compaction of the Seabed

et al. 2018

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The water entry problem of three-dimensional pounders with different geometric shapes of cube, cylinder, sphere, pyramid, and cone was numerically simulated by the commercial software Abaqus, and the effects of pounder shape and drop height from the free surface of water on deepwater displacement and velocity as well as pinch-off time and depth were investigated. An explicit dynamic analysis method was employed to model fluid-structure interactions using a Coupled Eulerian-Lagrangian (CEL) formulation. The simulation results are verified by showing the computed shape of the air cavity, displacement of sphere, pinch-off time, and depth which all agreed with the experimental results. The results reveal that the drag force of water has the highest and lowest effect on cubical and conical pounders, respectively. Increasing the pounder drop height up to the critical height leads to increased pounder velocity while impacting the model bed and more than the critical drop height has a reverse effect on pounder impact velocity. Pinch-off time is a very weak function of pounder impact velocity; but pinch-off depth increases linearly with increased impact velocity.

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“…Chen et al studied water entry of a horizontal cylinder based on VOF method by Fluent [18]. Ghadimi et al utilized FLOW-3D code to study the water entry of a circular cylinder and conducted a comparison between the linear and nonlinear solutions [19]. Tassin et al investigated water impact problem of a body with time-varying shape by CFD code OpenFOAM [20].…”

Section: Modelling and Simulation In Engineeringmentioning

confidence: 99%

Numerical Modeling and Simulation of Wave Impact of a Circular Cylinder during the Submergence Process

Jiang

Cai

2017

Modelling and Simulation in Engineering

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Wave slamming loads on a circular cylinder during water entry and the subsequence submergence process are predicted based on a numerical wave load model. The wave impact problems are analyzed by solving Reynolds-Averaged Navier-Stokes (RANS) equations and VOF equations. A finite volume approach (FV) is employed to implement the discretization of the RANS equations. A two-dimensional numerical wave tank is established to simulate regular ocean waves. The wave slamming problems are investigated by deploying a circular cylinder into waves with a constant vertical velocity. The present numerical method is validated using other numerical or theoretical results in accordance with varying free surface profiles when a circular cylinder sinks in calm water. A numerical example is given to show the submergence process of the circular cylinder in waves, and both free surface profiles and the pressure distributions on the cylinder of different time instants are obtained. Time histories of hydrodynamic load on the cylinder during the submergence process for different wave impact angles, wave heights, and wave periods are obtained, and results are analyzed in detail.

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Study of water entry of circular cylinder by using analytical and numerical solutions

Cited by 36 publications

References 14 publications

Experimental Study of the Wedge Effects on the Performance of a Hard-chine Planing Craft in Calm Water

Experimental Study of the Wedge Effects on the Performance of a Hard-chine Planing Craft in Calm Water

Numerical Investigation of Water Entry Problem of Pounders with Different Geometric Shapes and Drop Heights for Dynamic Compaction of the Seabed

Numerical Modeling and Simulation of Wave Impact of a Circular Cylinder during the Submergence Process

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