An Experimental Study on Hydrodynamic Characteristics of a Control Fin for a Supercavitating Underwater Vehicle

2018 ◽  
Vol 55 (1) ◽  
pp. 75-82
Author(s):  
So-Won Jeong ◽  
Sang-Tae Park ◽  
Byoung-Kwon Ahn
Keyword(s):  
Experimental Study ◽  
Underwater Vehicle ◽  
Hydrodynamic Characteristics

Analysis of Hydrodynamic Characteristics in the Process of Autonomous Underwater Vehicle Docking

2015 ◽  
Author(s):  
Xiaoxu Du ◽  
Huan Wang
Keyword(s):  
Drag Coefficient ◽  
Autonomous Underwater Vehicle ◽  
Simple Algorithm ◽  
Underwater Vehicle ◽  
Navier Stokes ◽  
Hydrodynamic Characteristics ◽  
Successful Operation ◽  
Underwater Docking ◽  
Computational Fluid Dynamics Cfd ◽  
Volume Method

The successful operation of an Autonomous Underwater Vehicle (AUV) requires the capability to return to a dock. A number of underwater docking technologies have been proposed and tested in the past. The docking allows the AUV to recharge its batteries, download data and upload new instructions, which is helpful to improve the working time and efficiency. During the underwater docking process, unsteady hydrodynamic interference occurs between the docking device and an AUV. To ensure a successful docking, it is very important that the underwater docking hydrodynamics of AUV is understood. In this paper, numerical simulations based on the computational fluid dynamics (CFD) solutions were carried out for a 1.85m long AUV with maximum 0.2 m in diameter during the docking process. The two-dimensional AUV model without fin and rudder was used in the simulation. The mathematical model based on the Reynolds-averaged Navier-Stokes (RANS) equations was established. The finite volume method (FVM) and the dynamic structured mesh technique were used. SIMPLE algorithm and the k-ε turbulence model in the Descartes coordinates were also adopted. The hydrodynamics characteristics of different docking states were analyzed, such as the different docking velocity, the docking device including baffle or not. The drag coefficients of AUV in the process of docking were computed for various docking conditions, i.e., the AUV moving into the docking in the speed of 1m/s, 2m/s, 5m/s. The results indicate that the drag coefficient increases slowly in the process of AUV getting close to the docking device. When the AUV moves into the docking device, the drag coefficient increases rapidly. Then the drag coefficient decreases rapidly. The drag coefficient decreases with the increase of velocity when AUV enters the docking device. It was also found that the drag coefficient can be effectively reduced by dislodging the baffle of docking device.

Hydrodynamic characteristics of vertical and quadrant face pile supported breakwater under oblique waves

2021 ◽  
pp. 147509022110313
Author(s):  
T J Jemi Jeya ◽  
V Sriram ◽  
V Sundar
Keyword(s):  
Experimental Study ◽  
Hydrodynamic Performance ◽  
Hydrodynamic Characteristics ◽  
Scattering Parameter ◽  
Oblique Waves ◽  
Test Conditions ◽  
Relative Water ◽  
Identical Test ◽  
Run Up ◽  
Water Depths

This paper presents the results from a comprehensive experimental study on the Quadrant Face Pile Supported Breakwater (QPSB) in two different water depths exposed to three different oblique wave attacks. The results are compared with that for a Vertical face Pile Supported Breakwater (VPSB) for identical test conditions. The paper compares the reflection coefficient, transmission coefficient, energy loss coefficient, non-dimensional pressure, and non-dimensional run-up as a function of the relative water depth and scattering parameter. The results obtained for QPSB are validated with existing results. The salient observations show that QPSB experiences better hydrodynamic performance characteristics than the VPSB under oblique waves.

A Study on the Hydrodynamic Characteristics of a Synthetic Jet Propelled Underwater Vehicle

2019 ◽  
Vol 35 (2) ◽  
pp. 115-125
Author(s):  
Chao Wang ◽  
Yang Lin ◽  
Lingbo Geng ◽  
Zhiqiang Hu
Keyword(s):  
Underwater Vehicle ◽  
Synthetic Jet ◽  
Hydrodynamic Characteristics

Experimental Study on the Hydrodynamic Characteristics of a Submersible Fish Cage at Various Depths in Waves

2019 ◽  
Vol 18 (3) ◽  
pp. 701-709 ◽  
Author(s):  
Shengcong Liu ◽  
Chunwei Bi ◽  
Hui Yang ◽  
Liuyi Huang ◽  
Zhenlin Liang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Hydrodynamic Characteristics

Hydrodynamic Characteristics of a Mechanical Pectoral Fin

1999 ◽  
Vol 121 (3) ◽  
pp. 605-613 ◽  
Author(s):  
Naomi Kato
Keyword(s):  
Vortex Lattice ◽  
Thrust Force ◽  
Underwater Vehicle ◽  
Hydrodynamic Characteristics ◽  
Pectoral Fin ◽  
Lattice Method ◽  
Unsteady Forces ◽  
Vortex Lattice Method ◽  
New Device ◽  
Phase Differences

This paper describes the use of a mechanical pectoral fin as a new device for maneuvering and stabilizing an underwater vehicle. The mechanical pectoral fin consists of two servo-motors generating a feathering motion and a rowing motion. The hydrodynamic characteristics of the device were analyzed experimentally and theoretically. The mechanical pectoral fin generates a thrust force in a range of phase differences between both motions. The unsteady vortex-lattice method, which takes into account the effects of viscosity, reasonably expresses the unsteady forces acting on the mechanical pectoral fin.

scholarly journals Experimental Study of the Influence of Gas Flow Rate on Hydrodynamic Characteristics of Sieve Trays and Their Effect on CO2 Absorption

2021 ◽  
Vol 11 (22) ◽  
pp. 10708
Author(s):  
Adel Almoslh ◽  
Falah Alobaid ◽  
Christian Heinze ◽  
Bernd Epple
Keyword(s):  
Experimental Study ◽  
Pressure Drop ◽  
Flow Rate ◽  
Gas Flow ◽  
Water System ◽  
Volumetric Flow Rate ◽  
Hydrodynamic Characteristics ◽  
Co2 Absorption ◽  
Gas Flow Rate ◽  
Sieve Tray

An experimental study was conducted in the sieve tray column to investigate the influence of gas flow rate on the hydrodynamic characteristics of the sieve tray, such as total tray pressure drop, wet tray pressure drop, dry tray pressure drop, clear liquid height, liquid holdup, and froth height. The hydrodynamic characteristics of the sieve tray were investigated for the gas/water system at different gas flow rates from 12 to 24 Nm3/h and at different pressures of 0.22, 0.24, and 0.26 MPa. In this study, a simulated waste gas was used that consisted of 30% CO2 and 70% air. The inlet volumetric flow rate of the water was 0.148 m3/h. The temperature of the inlet water was 19.5 °C. The results showed that the gas flow rate has a significant effect on the hydrodynamic characteristics of the tray. The authors investigated the effect of changing these hydrodynamic characteristics on the performance of a tray column used for CO2 capture.

scholarly journals Numerical Investigation on Air Film Fusion of Pressure-Equalizing Exhaust around Shoulder Ventilation of Submarine-Launched Vehicle

2021 ◽  
Vol 10 (1) ◽  
pp. 39
Author(s):  
Yao Shi ◽  
Jinyi Ren ◽  
Shan Gao ◽  
Guang Pan
Keyword(s):  
Numerical Calculation ◽  
Surface Pressure ◽  
Flow Model ◽  
Axial Direction ◽  
Underwater Vehicle ◽  
Hydrodynamic Characteristics ◽  
Circumferential Fusion ◽  
Numerical Calculation Method ◽  
Rng Turbulence Model ◽  
Air Film

In order to study the influence of pressure-equalizing exhaust at the shoulder of a submarine-launched vehicle on the surface hydrodynamic characteristics, this paper establishes a numerical calculation method based on the VOF multiphase flow model, the standard RNG turbulence model and the overset mesh technology; the method compares the fusion characteristics of the air film at the shoulder of the underwater vehicle, as well as the distribution of surface pressure along the vehicle’s axial direction. The results show that the approximate isobaric zone derived from air film fusion can greatly improve the hydrodynamic characteristics of the vehicle, and the number of venting holes determines the circumferential fusion time of the air film. The greater the number of venting holes, the sooner circumferential fusion starts.

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