The Analysis of Optimal Oscillation Angle of Fin in Propulsion Device of Wave Glider Based on Quasisteady Hydrodynamic Method
- Zhongqiang Zheng (Ocean University of China, Key lab of Ocean Engineering of Shandong Province) | Zhenjiang Yu (Ocean University of China) | Zongyu Chang (Ocean University of China, Key lab of Ocean Engineering of Shandong Province) | Xiujun Sun (College of Oceanic and Atmospheric Sciences) | Zhanxia Feng (Ocean University of China) | Jiakun Zhang (Ocean University of China) | Haoran Zhao (Ocean University of China)
- Document ID
- International Society of Offshore and Polar Engineers
- The 28th International Ocean and Polar Engineering Conference, 10-15 June, Sapporo, Japan
- Publication Date
- Document Type
- Conference Paper
- 2018. International Society of Offshore and Polar Engineers
- Relative Motion, Hydrodynamic, Wave glider, Optimized angle
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- 13 since 2007
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Wave glider is a new type of mobile ocean observation platform. It has the advantages of long-term observation, free energy supply, no carbon submission, low vibration and noise etc. The key problem is how to improve the efficiency of wave energy utilization and increase the vehicle’s speed. Wave glider is driven by the underwater propulsion device, on which the oscillation angle of fin is the key factor affecting wave energy utilization. In this paper, the optimal rotational angle of fin was analyzed by computer fluid dynamic method (CFD). The hydrodynamic model of underwater propulsion device was developed based on relative motion principle and quasi-steady assumption. The result of pressure distribution, velocity distribution, vortex structure and propulsive force were obtained by numerical simulation. The relationship among the optimal oscillation angle, heaving speed and forward speed were developed. This work is helpful for the design of underwater propulsion mechanism of wave glider and control of fin rotation.
With the development of marine exploitation and the protection of the marine environment, many marine observation devices have been utilized. All kinds of marine observation are emerging constantly, such as AUV (autonomous underwater vehicle), ROV (remotely operated vehicle), manned submersible (for example JiaoLong), USV (Unmanned Surface Vessel), sea glider and so on. The operating range of these devices is restricted by the amount of carrying energy (most batteries) and the endurance is also limited. The sea glider still needs energy to actuate. The communication will discontinue because it should alternately move up and down to surface.
American Liquid Robotics Inc. has developed a wave driven unmanned surface vehicle (WUSV) as shown in Fig. 1, also called wave glider, composed of a floating body and underwater propulsion device, through a flexible cable to transfer the energy and communication.
The Wave Glider is propelled by forward thrust converted from wave energy, regardless of the wave direction (Fig. 2). The wave energy propulsion system is purely mechanical. That is to say, no energy is generated by the propulsion mechanism. Just as an airplane’s forward motion through the air allows its wings to create an upward lifting force, the submerged glider’s vertical motion through the comparatively still waters at the glider’ s depth allows its wings to convert a portion of this upward motion into a forward propulsion force. As waves pass by on the surface, the submerged glider acts as a tug pulling the surface float along a predetermined course. Separation of the glider from the float is a crucial aspect of the vehicle design.
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