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1

Hydrodynamic body shape analysis and their impact on swimming performance

Li T-Z., Zhan J.-M.

Acta of Bioengineering and Biomechanics

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2015

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Vol. 17, no. 4

3--11

EN

This study presents the hydrodynamic characteristics of different adult male swimmer's body shape using computational fluid dynamics method. This simulation strategy is carried out by CFD fluent code with solving the 3D incompressible Navier–Stokes equations using the RNG k-ε turbulence closure. The water free surface is captured by the volume of fluid (VOF) method. A set of full body models, which is based on the anthropometrical characteristics of the most common male swimmers, is created by Computer Aided Industrial Design (CAID) software, Rhinoceros. The analysis of CFD results revealed that swimmer’s body shape has a noticeable effect on the hydrodynamics performances. This explains why male swimmer with an inverted triangle body shape has good hydrodynamic characteristics for competitive swimming.

2

Modeling of a Water Flow Over Stepped Spillways

Kherbache K., Chesneau X., Abide S., Benmamar S.

Machine Dynamics Research

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2013

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Vol. 37, No. 1

51-68

EN

In this work, a numerical analysis of the flow over a stepped spillway is performed. The free surface flow is described by the Reynolds Averaged Navier-Stokes equation (RANS) coupled to k-ε model. These equations are solved using a commercial software based on the finite volume scheme and the VOF method. We analyzed the influence of the steps shape and water flow rate on velocity, turbulence dissipation rate and pressure distributions. In this, we found that the maximum values of the static pressure and the turbulence dissipation rate increase as the discharge increases and the main flow velocity is greater than the one of the secondary flow.

3

Relaxation and breakup of a cylindrical liquid column

Ali M., Umemura A.

International Journal of Applied Mechanics and Engineering

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2011

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Vol. 16, no 1

257-270

EN

Instability of a capillary wave and breakup of a square cylindrical liquid column during its relaxation have been investigated numerically by simulating three-dimensional Navier-Stokes equations. For this investigation a computer code based on the volume-of-fluid (VOF) method has been developed and validated with published experimental results. The result shows that the agreement of numerical simulation is quite good with the experimental data. The code is then used to study the capillary wave and breakup phenomena of the liquid column. The investigation shows the underlying physics during relaxation of the square cylindrical liquid column, illustrates the formation and propagation of the capillary wave and breakup processes. The breakup behavior for the present configuration of the liquid column shows some significant differences from those predicted by conventional jet atomization theories. The formation of the capillary wave is initiated by the surface tension on the sharp edge of the square end of the cylinder and the propagation of the wave occurs due to the effect of surface tension force on the motion of the fluid. The propagation of the capillary wave to the end of the liquid column causes a disturbance in the system and makes the waves unstable which initiates the breakup of the liquid column. The characteristics of the capillary wave show that the amplitude of the swell grows faster than the neck of the wave and that of the tip wave grows much faster than other waves. The velocity of the liquid particle is dominated by the pressure in the liquid column.