Numerical Analysis of the Motion of an Automated Fish Guiding System for Set Net Fishery

A two-dimensional kinematic analysis model for predicting the motion of the hose net was developed. The water tank test was also carried out for validation of the model. As a result of the water tank test, the hose net was raised in the way that fish are guided in the fish catching area. The variation in the two-dimensional formation of the hose net was analyzed using a lumped mass method. When the hose net contains air, bending stress is generated on the flexible hose according to the internal pressure. Therefore, the effect of bending stiffness was considered. Although the formation of the hose net differs when compared one to one due to the varied air injection rate in the flexible hose, the simulated formation corresponds well to the observed one at the latter half of the numerical analysis. However, the discrepancy could be found in the initial stage of the flotation. This discrepancy will be caused by the inaccurate modeling of the air flow in the flexible hose and to the simplification by using two-dimensional model. Compressed air is inflated due to the decrease in water pressure that occurs when the hose net floats from deep water to shallow water. This phenomenon is a key factor for designing the hose net. The motion of the hose net may be controlled by regulating the compressor. As future studies, the compressive air flow in the hose net should be modeled in the future. Then the three-dimensional motion of the hose net and its interaction with the box chamber net should be predicted precisely. Finally, the two-dimensional model should be expanded to the three-dimensional model.