Numerical and experimental investigation of a six DOF scaled model of a swimmer posed in streamlined posture

Li, Tian zeng; Wai, Onyx W. H.; Gong, Ye jun; Zhan, Jie

doi:10.1016/j.compfluid.2017.02.022

Cited by 4 publications

(5 citation statements)

References 22 publications

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“…where k is the turbulent kinetic energy, ε is the turbulent dissipation rate, G k is the generation of turbulent kinetic energy due to the mean velocity gradients, G b is the turbulent kinetic energy that is determined by buoyancy, µ eff is the turbulent viscosity, In order to consider the effect of the water surface during swimming, a two-phase flow, including air and water, was involved in this study. The volume of fluid (VOF) method was used to track the deformation of the air-water interface [21]. Therefore, a new transport equation for the volume fraction of fluid was introduced.…”

Section: Governing Equationsmentioning

confidence: 99%

Hydrodynamic Characteristics of Different Undulatory Underwater Swimming Positions Based on Multi-Body Motion Numerical Simulation Method

Yang

Chen

et al. 2021

IJERPH

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The study of hydrodynamic characteristics of swimming is the main way to optimize the swimming movement. The relationship between position, water depth, and swimming performance of undulatory underwater swimming are one of the main concerns of scholars. Therefore, the aim of this study is to analyze the swimming performance of three different undulatory underwater swimming positions under various swimming depths using a numerical simulation method based on multi-body motion. The simulation was conducted using 3D incompressible Navier–Stokes equations using the RNG k-ε turbulence closure equations, and in combination with the VOF method thus that we could include the water surface in our calculations. Different swimming depths based on the distance from the shoulder joint center to the initial water surface were considered. The velocity of the shoulder joint center was captured with a swimming motion monitoring system (KiSwim) and compared with the calculated results. The study found that there was a significant difference in the hydrodynamic characteristics of the three undulatory underwater swimming positions (i.e., the dorsal, lateral, and frontal positions) when swimming near the water surface, and the difference decreased as the swimming depth increased. There was a negative correlation (R(dorsal) = −0.928, R(frontal) = −0.937, R(lateral) = −0.930) between the swimming velocities of the three undulatory underwater swimming positions and the water depth (water depth = 0.2–0.7 m) and that the lateral position had the greatest average velocity. Therefore, it is recommended that swimmers travel at least 0.5 m below the water surface in any undulatory underwater swimming position in order to avoid excessive drag forces. As the swimmer approaches the water surface, the lateral position is worth considering, which has better velocity and hydrodynamic advantage than the other two undulatory underwater swimming positions.

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Section: Governing Equationsmentioning

confidence: 99%

Hydrodynamic Characteristics of Different Undulatory Underwater Swimming Positions Based on Multi-Body Motion Numerical Simulation Method

Yang

Chen

et al. 2021

IJERPH

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“…A simplified 2D version of the 3D swimmer model introduced by Li et al (2017a) , Li et al (2017b) is employed as depicted in Figure 1 . The 3D swimmer model was constructed based on the mean anthropometrical characteristics of a group of Chinese male swimmers, featuring a streamlined prone posture with outstretched arms, overlapping hands, straightened legs, closed feet, and flexed plantar.…”

Section: Methodsmentioning

confidence: 99%

“… Barbosa et al (2015) evaluated the relative contributions of form drag and frictional drag to total passive drag. Li et al (2017a) studied the hydrodynamic characteristics and surrounding vortex structures of a swimmer gliding with six degrees of freedom. For more information, the reader is referred to the review papers of Naemi et al (2010) and Scurati et al (2019) .…”

Section: Introductionmentioning

confidence: 99%

Analysis of fluid force and flow fields during gliding in swimming using smoothed particle hydrodynamics method

Liu,

Yu,

Meng

et al. 2024

Front. Bioeng. Biotechnol.

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Gliding is a crucial phase in swimming, yet the understanding of fluid force and flow fields during gliding remains incomplete. This study analyzes gliding through Computational Fluid Dynamics simulations. Specifically, a numerical model based on the Smoothed Particle Hydrodynamics (SPH) method for flow-object interactions is established. Fluid motion is governed by continuity, Navier-Stokes, state, and displacement equations. Modified dynamic boundary particles are used to implement solid boundaries, and steady and uniform flows are generated with inflow and outflow conditions. The reliability of the SPH model is validated by replicating a documented laboratory experiment on a circular cylinder advancing steadily beneath a free surface. Reasonable agreement is observed between the numerical and experimental drag force and lift force. After the validation, the SPH model is employed to analyze the passive drag, vertical force, and pitching moment acting on a streamlined gliding 2D swimmer model as well as the surrounding velocity and vorticity fields, spanning gliding velocities from 1 m/s to 2.5 m/s, submergence depths from 0.2 m to 1 m, and attack angles from −10° to 10°. The results indicate that with the increasing gliding velocity, passive drag and pitching moment increase whereas vertical force decreases. The wake flow and free surface demonstrate signs of instability. Conversely, as the submergence depth increases, there is a decrease in passive drag and pitching moment, accompanied by an increase in vertical force. The undulation of the free surface and its interference in flow fields diminish. With the increase in the attack angle, passive drag and vertical force decrease whereas pitching moment increases, along with the alteration in wake direction and the increasing complexity of the free surface. These outcomes offer valuable insights into gliding dynamics, furnishing swimmers with a scientific basis for selecting appropriate submergence depth and attack angle.

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“…The Reynolds number was approximately 3.6 × 10 6 based on the swimmer's cross section. According to our previous study [16], the minimum grid on the swimmer model was set to 0.005 m, and the total y+ was between 32 and 160, which met the requirements of the simulation model. ANSYS FLUENT V19.0 was used to determine the governing equations.…”

Section: Computational Domain and Numerical Simulationmentioning

confidence: 99%

“…Recently, unsteady simulations have been used to study the dolphin kick [4,6,7,10,15,16]. Loebbecke et al [4,7] and Hochstein et al [15] showed that most of the thrust force was generated by the feet during kicking.…”

Section: Introductionmentioning

confidence: 99%

The Effect of the Swimmer’s Trunk Oscillation on Dolphin Kick Performance Using a Computational Method with Multi-Body Motion: A Case Study

Chen

Yang

et al. 2022

IJERPH

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The effect of a specific Chinese swimmer’s trunk oscillation on dolphin kick was investigated in order to optimize competitive swimming movement. Using a numerical simulation method based on multi-body motion, different swimmer’s trunk oscillation during a dolphin kick was analyzed. The simulation was conducted using 3D incompressible Navier–Stokes equations and renormalization group k-ε turbulence model, combined with the Volume of Fluid method to capture the water surface. The simulation’s results were evaluated by comparing them with experimental data and with previous studies. The net streamwise forces, mean swimming velocity, and joint moments were also investigated. There was a positive correlation between the mean swimming velocity and the amplitudes of the swimmer’s trunk oscillation, where the Pearson correlation coefficient was 0.986 and the selected model was statistically significant (p < 0.05). In addition, as the mean swimming velocity increased from 1.42 m/s in Variant 1 to 2 m/s in Variant 5, the maximum positive moments of joints increased by about 24.7% for the ankles, 27.4% for the knees, −3.9% for the hips, and 5.8% for the upper waist, whereas the maximum negative moments of joints increased by about 64.5% for the ankles, 28.1% for the knees, 23.1% for the hips, and 10.1% for the upper waist. The relationship between the trunk oscillation and the vortices was also investigated. Therefore, it is recommended that swimmers should try to increase the amplitudes of trunk oscillation to increase their swimming velocity. In order to achieve this goal, swimmers should increase strength training for the ankles, knees, and upper waist during the upkick. Moreover, extra strength training is warranted for the ankles, knees, hips, and upper waist during the downkick.

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Numerical and experimental investigation of a six DOF scaled model of a swimmer posed in streamlined posture

Cited by 4 publications

References 22 publications

Hydrodynamic Characteristics of Different Undulatory Underwater Swimming Positions Based on Multi-Body Motion Numerical Simulation Method

Hydrodynamic Characteristics of Different Undulatory Underwater Swimming Positions Based on Multi-Body Motion Numerical Simulation Method

Analysis of fluid force and flow fields during gliding in swimming using smoothed particle hydrodynamics method

The Effect of the Swimmer’s Trunk Oscillation on Dolphin Kick Performance Using a Computational Method with Multi-Body Motion: A Case Study

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