Experimental and Numerical Study on Hydrodynamic Performance of an Underwater Glider

Liu, Yanji; Ma, Ji; Ma, Ning; Huang, Zhijian

doi:10.1155/2018/8474389

Cited by 3 publications

(2 citation statements)

References 17 publications

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“…where k is the turbulent kinetic energy, ε is the turbulent dissipation rate, μ t � ρC u k 2 /ε is the turbulent viscosity, G k is the turbulent kinetic energy term generated by the velocity gradient, C 1ε and C 2ε are empirical constants, and σ k and σ ε are the Prandtl number of turbulent kinetic energy and dissipation rate, respectively. For the values of empirical constants, C 1ε and C 2ε are 1.44 and 1.92, respectively, σ k and σ ε are 1.0 and 1.3, respectively, and C u is 0.09 [29,30].…”

Section: Mathematical Problems In Engineeringmentioning

confidence: 99%

Numerical Simulation on Flow Field and Design Optimization of a Generator Unit Based on Computational Fluid Dynamics Analysis

Tan

Yuan

et al. 2021

Mathematical Problems in Engineering

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Achieving an optimal cooling of the generator unit is indispensable for high working performance. In this work, computational fluid dynamics analysis on the flow field of the conventional type and silent type of the S688CCS series generator unit is conducted, and design optimization of the generator unit with poor cooling is studied based on flow field analysis results. Flow field simulation results indicate that the total cooling air quantity of the silent type generator unit is lower than that of the conventional type generator unit, and the cooling air quantity of the radiator is also lower than that of the conventional type generator unit, which is not conductive for the cooling of the silent type generator unit. The flow field optimization is achieved by adopting the single variable control method to improve the structure of the fan cover, silent components for silence, adjacent structure, and air inlet grille. The corresponding structure optimization scheme is put forward. After optimization, the air quantity for the cooling radiator of the silent type generator unit is 44.33% higher than that of its original structure, and the total cooling air quantity is higher than that of the conventional type generator unit. The research results in this work can provide a theoretical basis for the design of the cooling air flow path of generator units for achieving an optimal cooling performance.

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Section: Mathematical Problems In Engineeringmentioning

confidence: 99%

Numerical Simulation on Flow Field and Design Optimization of a Generator Unit Based on Computational Fluid Dynamics Analysis

Tan

Yuan

et al. 2021

Mathematical Problems in Engineering

View full text Add to dashboard Cite

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“…In their research, reducing the wing thickness along its length increases lift force and reduces dynamic stability. Liu et al [29] applied the hydrodynamic coefficients obtained from the numerical method of rotational motion of the glider with good accuracy according to the experimental results using the dynamic model method. Javaid et al [30] studied the hydrodynamic properties of their gliders in different conditions.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Hydrodynamic Properties of Alex Type Gliders

Divsalar

Shafaghat

Farhadi

et al. 2020

IJE

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This work presents a numerical Simulation of an underwater glider to investigate the effect of angle of attack on the hydrodynamic coefficients such as lift, drag, and torque. Due to the vital role of these coefficients in designing the controllers of a glider, and to obtain an accurate result, this simulation has been carried on at a range of operating velocities. The total length of the underwater glider with two wings is 900 mm with a 4-digits NACA0009 profile. The fluid flow regime is discretized and solved by computational fluid dynamics and finite volume method. Since the Reynolds number range for this study is in a turbulent flow state (up to 3.7e06), the κ-ω SST formulation was used to solve Navier-Stokes equations and continuity and the angles of attack ranging are from-8 to 8 degrees. The main purpose of this research is to study the effect of each of the dynamics parameters of glider motion such as velocity and angle of attacks on the hydrodynamic coefficients. Based on the results, the drag and lift coefficients are enhanced with increasing the angle of attack. In addition, the drag coefficient enhanced with increasing the velocity however, when the glider velocity is increased, the lift coefficient does not change significantly except at the highest angle of attack that decreases. The highest drag coefficient is 0.0246, which corresponds to the angle of attack of-8 and the Reynolds number of 3738184. In addition to simple geometry, the glider studied in this paper shows relatively little resistance to flow.

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Hydrodynamic Performance Enhancement of Torpedo-Shaped Underwater Gliders Using Numerical Techniques

2024

F1000Res

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Background Underwater gliders are widely used in marine applications for monitoring purposes. These gliders must withstand hydrodynamic forces and maintain its body stability. The underwater environments are highly unpredictable, and small changes in the environment can lead to significant instability in underwater vehicles. Methods This study uses different numerical techniques to investigate the hydrodynamic characteristics of a torpedo-shaped glider. A symmetric torpedo-shaped glider model was created and analyzed using a licensed version of ANSYS 20.1 Fluent tool. The behavior of the torpedo glider under various flow conditions was examined such as variation of grid test, change of turbulent models, the variation in the inflow boundary conditions involves varying the velocity from 10.16 m/s to 15.16 m/s in 1m/s increment and from 10.16 m/s to 7.66 m/s in 0.5 m/s, also six different models were analyzed. Results Research was also attempted with different turbulent models and the Spalart-Allmara model was producing least validation error of 1.28 % with a primary focus on nose optimization. By varying the nose length, the study aimed to identify the best-suited nose geometry to minimize drag force. The nose lengths were varied to 0.205 m and 0.19m, resulting in validation errors of 2.81% and 1.16%, respectively, the results are clearly explained in the sub sequent sections of this article. Conclusion In conclusion, this study has evaluated various modifications and their impact on drag force reduction. The application of Spallart-Allmara model resulted in an improvement of 1.28%. Decrease in velocity lead to a significant reduction in the drag force, with an improvement of 37.3%. The nose optimization also contributed to drag force; a nose length of 0.205m yielded a 3.37% improvement. While a 0.19m nose length resulted in a 1.67% reduction. This study helps researchers in hydrodynamics by optimizing geometry for drag reduction.

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Experimental and Numerical Study on Hydrodynamic Performance of an Underwater Glider

Cited by 3 publications

References 17 publications

Numerical Simulation on Flow Field and Design Optimization of a Generator Unit Based on Computational Fluid Dynamics Analysis

Numerical Simulation on Flow Field and Design Optimization of a Generator Unit Based on Computational Fluid Dynamics Analysis

Numerical Simulation of Hydrodynamic Properties of Alex Type Gliders

Hydrodynamic Performance Enhancement of Torpedo-Shaped Underwater Gliders Using Numerical Techniques

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