Numerical and experimental investigation of a three dimensional spherical-nose projectile water entry problem

Erfanian, Mohammad Reza; Anbarsooz, Morteza; Rahimi, Nasrollah; Zare, Mohsen; Moghiman, Mohammad

doi:10.1016/j.oceaneng.2015.05.024

Cited by 45 publications

(15 citation statements)

References 25 publications

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“…It should be noted that the fluid was assumed to be viscous and compressible. Numerical simulations of solid-fluid interactions were performed using the Coupled Eulerian-Lagrangian (CEL) formulation and the remeshing techniques available in Abaqus 6.14-2 software [34]. The pounder was considered as a rigid solid and its mesh was created in Lagrangian form.…”

Section: Numerical Simulationsmentioning

confidence: 99%

“…The denominator of (34) should not be equal to zero; therefore, an extreme value is defined for and as lim = 1 ,…”

Section: Linear -Hugoniot Formmentioning

confidence: 99%

“…However, fluid expansion is confronted with fluid hydrostatic pressure resistance and as a result the radial flow direction is reversed, leading to cavity contraction and collapse. Cavity collapse occurs when the cavity wall moves inward, until the moment of pinch-off ( = 70.8 ms), and the cavity is divided into two separated parts [34]. While the lower cavity sticks to the sphere and moves along with it, the upper cavity continues its contraction and moves towards the water's surface.…”

Section: Validationmentioning

confidence: 99%

“…After entering the water, a symmetric air cavity is formed behind the pounders. Air cavity formation involves several steps including air cavity creation and expansion behind the pounder, air cavity contraction, and air cavity collapse [34]. As the pounder moves downward in water depth, it imposes a force onto surrounding fluid in its radial directions and transfers its momentum to the fluid.…”

Section: Drop Height and Impact Velocity Of Poundersmentioning

confidence: 99%

“…In the other words, the air cavity contraction is accelerated until pinch-off occurs and the air cavity is divided into two distinct parts. The upper part of the air cavity continues its contraction and moves towards the water's surface, whereas the lower part of the air cavity clings to the pounder and moves along with it [34]. After impacting the water surface, the cubical and cylindrical pounders due to their flat contact surfaces lose some of their velocity.…”

Section: Drop Height and Impact Velocity Of Poundersmentioning

confidence: 99%

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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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Section: Numerical Simulationsmentioning

confidence: 99%

“…The denominator of (34) should not be equal to zero; therefore, an extreme value is defined for and as lim = 1 ,…”

Section: Linear -Hugoniot Formmentioning

confidence: 99%

Section: Validationmentioning

confidence: 99%

Section: Drop Height and Impact Velocity Of Poundersmentioning

confidence: 99%

Section: Drop Height and Impact Velocity Of Poundersmentioning

confidence: 99%