• 수산해양기술연구
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• 제35권2호
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• pp.201-208
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• 1999

To develop a new fish cage which is required for offshore or moving cage culturing system has been gradually increased against being closely dense of fish cage in shallow water. Though submersible fish cage culturing system is essential technology for converting from shallow water into the offshore, it was pointed out the serious problem about stability of which are sinking and floating state. This study is presented conceptual design of submersible fish cage centered with a mooring steel pile to acquire stability and faculty. Design of mooring steel pile for submersible fish cage culturing system needs to carry out optimal design of mooring steel pile for which much efforts are required. Formulation and optimal design process of submersible fish cage are organized into using Sequential Quadratic Programming method of numerical optimization. For submersible fish cage system centered with a mooring steel pile, process of the optimal design is proposed and the optimal solutions are obtained.

• 수산해양기술연구
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• 제32권2호
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• pp.117-124
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• 1996

The real size submersible fish cage($L{\times}B{\times}D$, $3{\times}3{\times}6$m)system consists of the compressed air equipment was made in order to control efficiently in case of heavy weather or environmental pollution such as red tide, and then carried out experiment on the submersible functions and safety for that cage at Koje inland sea in 14th June, 1995. The authors could confirm that the submersible cage was very stabilized it's submersible functions and safety when the cage was floating and sinking at sea.

• 드라이브 ㆍ 컨트롤
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• 제14권3호
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• pp.18-24
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• 2017

The purpose of this paper is to develop a new submersible fish cage operated by a pneumatic system for offshore aquaculture. Although some researchers have investigated modeling and control of fish cages, such cages consist of variable ballast tanks that with closed cylinders and thus present a maintenance issue. In solving the issue the new submersible fish cage investigated consists of bottom-opening cylinders. Accordingly, we designed a mathematical model of the concept and applied Sliding Mode Control for nonlinear angle control. Some experiments conducted under assumed conditions indicate that the angle of the system converges to zero under all conditions and the control has the stability to balance the fish cage.

• 수산해양기술연구
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• 제43권1호
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• pp.38-48
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• 2007

Numerical modeling was used to evaluate the submerging characteristics of the submersible fish cage system operated by compressed air. The submerging characteristics calculated by numerical analysis as the cage was moved up and down were nearly identical to existing experiment results. Thus, the numerical model proposed in this study could be very useful in analyzing various parameters required for optimizing the design of a submersible fish cage system operated by compressed air.

• Journal of Advanced Marine Engineering and Technology
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• 제35권5호
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• pp.690-699
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• 2011

A numerical model analysis was performed to analyze the stability of the mooring lines of an automatic submersible fish cage system in waves and currents. The fish cage system consisted of a 12-angled rigid frame, net cage, cover net, 12 upper floats, 12 tanks(for fixed and variable ballast), mooring lines, anchors, and a control station. Simulations were performed with the cage at the surface of the water and at a depth of 20 m. A Morison equation type model was used for simulations of the system in two configurations. The force parameters described both regular and random waves, with and without currents, and their values were input to the model. Mooring tension calculations were conducted on the mooring lines, grid lines and lower bridle lines of the cage. The stability of the mooring lines was checked under both static and dynamic conditions.

• 수산해양기술연구
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• 제46권1호
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• pp.20-31
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• 2010

In this research, the submersible fish cage was designed to avoid structural and biological damage during harsh sea conditions. The submersible cage system consists of netting, mooring ropes, a floating collar, floats, sinkers and anchors. Whole elements of the cage were modeled on the mass-spring model. The computer simulations were carried out to investigate the dynamic behavior of the cage and to calculate mooring line tension subjected to tidal currents and waves. As expected, the tension values in the mooring line of the submerged position are 36% less compared to that of the surface cage under the same loading conditions. As the wave was used in combination with the current velocity of 1m/s, the average tensile load for the submerged cage showed 85% of the value for the floating cage. The simulation results provide an improved understanding of the behaviors of the structure and valuable information on the optimized design of the cage system exposed to open ocean environmental factors.

• 수산해양기술연구
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• 제44권1호
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• pp.46-56
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• 2008

A numerical model analysis was performed to analyze the motion and mooring tension response of submersible fish cage systems in irregular waves and currents. Two systems were examined: a submersible cage mooring with a single, high tension mooring and the same system, but with an additional three point mooring. Using a Morison equation type model, simulations of the systems were conducted with the cage at the surface and submerged. Irregular waves(JONSWAP spectrum) with and without a co-linear current with a magnitude of 0.5m/s were simulated into the model as input parameters. Surge, heave and pitch dynamic calculations were made, along with tension responses in the mooring lines. Results were analyzed in both the time and frequency domains and linear transfer functions were calculated.

• 수산해양기술연구
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• 제48권1호
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• pp.40-50
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• 2012

This study aims to analyze the performance of a submersible fish cage which was designed for developing an economical cage system can be applied in korean aquaculture environment easily. To analyze the performance of the designed cage a model test was carried out. In the test, inclination changes of the upper frame and mooring tensions of model cage were measured during the submerging and surfacing motion in still water and wave condition (period: 2s, wave height: 0.1, 0.2, 0.3m). As a result, in the still water condition the model cage kept horizontal balance and inclination degree of the upper frame was about $1^{\circ}$. In the wave condition, the model cage showed bilateral symmetric up-and-down motion but the average inclination degree of the upper frame was about $0^{\circ}$. When the model cage reached at a depth of 1m, the up-and-down motion of the cage was decreased by 12% compared with that of at the surface (period 2s, height 0.3m). In the same wave condition, the maximum and average line tension under the bottom position were about 8% and 11% respectively compared with that of at surface.

• Journal of Advanced Marine Engineering and Technology
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• 제34권5호
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• pp.743-749
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• 2010

자동 부침식 가두리 시설을 개발하기 위해 가두리 시설을 구형 부자로 단순화하여 이것의 자동 침하 및 상승 관련 제어 알고리즘 및 프로그램을 개발하였고 실내 수조 실험을 통해 그 유용성을 확인하였다. 또한 기존 연구 결과의 수치와도 비교 분석함으로써 기존 연구의 수치 모델 결과의 유용성을 재확인하게 되었다. 그리고 실물 실험에 대한 선행 연구로써 많은 변수들과 부력에 대한 비선형적인 메커니즘을 제어를 통해 극복하였으며, 이는 실물 실험에 있어 중요한 요소로 작용될 것이다.