Analysis Of Ship Motion Characteristics And Its Influence On Comfort Under Wind And Wave Excitation

As a luxurious water entertainment vessel,cruise ships not only pursue unique appearance,a full range of entertainment facilities,and a variety of sailing routes,but also have more stringent requirements on the comfort of passengers for motion.On the basis of meeting the safety design,the cabin conditions are continuously improved to obtain a better amusement experience.Because the target of this paper is not yet designed and built for medium-sized cruise ships,but the route has been determined,and the comfort evaluation method involved in this article can be applied to other ship types.Therefore,this paper selects an oil tanker with similar data and complete data as the research object,analyzes the influence of different environmental factors on the movement characteristics of the oil tanker under the action of wind and wave excitation load,and combines the incidence of motion sickness and the evaluation of comprehensive sports comfort index The comfort level of the tanker.The main research contents include:（1）Numerical simulation of ship wind load.The fluid domain model of the external wind field of the target tanker is established,and CFD simulation analysis is performed.Through the Reynolds number independence verification,it was found that the constant wind speed at different inlets has almost no effect on the calculated wind load coefficient,and the results of the wind load coefficient obtained by CFD simulation and commonly used calculation methods are in good agreement.The UDF program of exponential rate dynamic wind was compiled,and the velocity distribution and hull surface pressure distribution characteristics at each deck height were analyzed.（2）Research on ship motion characteristics under wind wave excitation.Based on the three-dimensional potential flow theory,the hydrodynamic model of the target tanker is established.The first-order wave force,second-order wave force,additional mass,radiant damping,and amplitude response RAO operator of the tanker are calculated and analyzed in frequency domain.Hydrodynamic characteristics are reasonably corrected for roll damping.Considering the wind load coefficient,under regular wave conditions,the effects of wave period,wave amplitude,and wave direction angle on the tanker’s motion response are analyzed;under irregular conditions,it is found that there is a large difference in motion response between different sea state levels and different positions on the ship.（3）Analysis of factors influencing the incidence of motion sickness MSI under regular wave conditions.The influence of factors such as wave period,amplitude and direction on the incidence of motion sickness incidence under regular wave conditions was studied.It was found that the incidence of motion sickness incidence was the smallest when the wave period was 8s.The incidence of motion sickness incidence decreases sharply;when the amplitude increases,the incidence of motion sickness incidence also increases;when the wave angle is around 90°,the incidence of motion sickness incidence is greater.And when the duration of exercise was 2h,the incidence of motion sickness incidence tended to be stable due to the body’s adaptation to low-frequency motion characteristics.（4）Analysis of influencing factors of MSI in motion sickness under irregular wave conditions.The effects of sea state levels and different positions of tankers on the incidence of motion sickness incidence under irregular wave conditions were studied,and it was found that as the sea state level increased,the incidence of motion sickness incidence increased sharply;The length of the ship decreases first and then increases.The values are larger near the stern and stern,and the smallest near the middle of the ship.In the width direction of the ship,the incidence of motion sickness incidence gradually increases from the middle longitudinal section to the left and right sides,and is the largest near the side of the ship.（5）Definition and calculation of OMSI index for general motion sickness.A calculation method for evaluating the incidence of motion sickness in ships under arbitrary sea conditions using the overall incidence index of general motion sickness was proposed,and the effect of two different wave angle probability distribution forms on the overall incidence of general motion sickness was considered.（6）Research on Evaluation Method of Ship Motion Comfort Based on Fuzzy Mathematics.The evaluation indexes of motion comfort are determined according to the relevant standards of ship’s wave resistance.Based on the fuzzy mathematical theory,each evaluation index is blurred and the membership function is established.According to the degree of influence of each evaluation index on motion comfort,the motion The comprehensive evaluation of the membership function of the comfort degree is used to classify the ship’s motion comfort,and the effectiveness of the proposed method is verified by examples of each sea state level.