RIASSUNTO
ABSTRACT
The research about the sloshing inside liquid tanks and the consequent boat's motions always attract much attention. Based on the three-dimensional potential flow theory and by means of analyzing the seine boat's motion under various working conditions, the hydrodynamic coefficients are obtained in frequency domain. By comparing the motion responses of seine boat under the sloshing and non-sloshing conditions respectively, it is found that liquid sloshing plays an important role in reducing the boat roll. Through the response comparison of seine boat's motion in different wave angles, it is found that the roll motion is sensitive to the variation of wave angles and that the seine boat's resonance frequency shifts attributing to the change of total filling rate and the order of fuel-freshwater consumption process. The consumption order and the liquid consumption residual have different effects on the seine boat's motion. Subsequently, a suitable consumption sequence is suggested, providing a reference for the practical loading process, consumption process and motion response analysis of seine boat.
INTRODUCTION
Since the 1990s, the methods for seine operation have developed rapidly, and fishing vessels have gradually changed from the trawl method to the seine method. For relatively small fishing boats, the hull swaying motion at a certain frequency will cause severe tank sloshing, and it will definitely aggravate the hull swaying, reduce the capacity of fishing, survivability of the ship and the habitability of the crew. Therefore, it is particularly important to carry out the coupling motion response prediction analysis of the tank sloshing and hull swaying.
In recent years, more and more scholars started to consider the problems of ship motion in tank sloshing. Sun et al. (2019) performed a multi-program comparison to get the FPSO coupling motion of two sloshing tanks, and they found that tank loading would change the roll resonance frequency. Wang et al. (2017) discussed the effects of tank layout on FSRU motion. Zhang et al. (2017) compared the roll motion of oil tankers with or without liquid cargo sloshing, and found that the increase of oil loading would exacerbate the tanker roll, and in certain loading, sloshing could have anti-rolling effect. Wu et al. (2008) made numerical simulations of the coupling motions of pitch and heave under head-wave navigation, with the subject of Wigley ship model. Dien et al. (2012) studied the effect of different ship types on the roll motion of small the seine boat and found that the ship type had a large effect on the roll motion. Kim et al. (2007) took the impulse response function method to get the linear motion of the ship and found that ship motion had strong sensitivity to wave slope. Weymouth et al. (2005) calculated the pitch and heave motion response of the ITTC S175 ship model under the heading wave, and analyzed the movement changes of the ship model in waves.