The Wind-Waves Prediction And Ship Motions Evaluation In Real Seas

Ocean wave is the main factor causing ship motions and has adverse effects on the offshore operations or tasks of ships.Hydrometeorological forecasts such as wind speed on the sea surface and wave height can provide auxiliary judgment information for ship navigation.Under this condition,specific control decisions often rely on the experience of drivers,and there is a lack of auxiliary decision-making method for direct and quantitative evaluation of ship navigation status using marine environmental information.Therefore,based on the wave model,this paper conducts medium and large-scale wave forecasting and a study on the evaluation of ship motions in real sea areas.It can provide a direct,quantitative and more accurate forecasting method for ship navigation safety and route planning,which is of great significance to the informatization and intelligent guarantee of ship navigation.Wind and wave simulation is the basis for the evaluation of ship motions in real seas.The third-generation wave model has matured and is widely used in the marine field.However,there is still a lack of wave model parameter schemes suitable for the coastal waters of China.To this end,the parameter optimization of wave simulation in offshore China was studied.The parameter optimization of the wave model was studied based on the open buoy data in the Yellow Sea.Considering that the white-capping dissipation coefficient plays an important role in wave simulation,the white-capping dissipation coefficient was optimized.The results show that the terrain resolution has no significant effect on the wave simulation results and the optimal white-capping dissipation coefficient is similar in the same season.Meanwhile,the ratio of the peak optimal white-capping dissipation coefficient to the global optimal whitecapping dissipation coefficient is close to a constant.Aiming at the problem of long calculation time of high-resolution wave simulation by wave model,this paper used the convolutional neural network(CNN)to build a regional wave prediction model.After optimizing the model structure and comparing the prediction accuracy and efficiency,the results show that taking the historical wave information into account in model input can significantly improve the prediction accuracy.The prediction model based on historical wave data has the highest prediction accuracy and higher computational efficiency than the wave model.Meanwhile,the CNN-based model shows great adaptability to different sea areas such as shallow sea areas and the sea area under extreme weather conditions.Meanwhile,the increase in computational efficiency makes the regional wave prediction model provide conditions for real-time evaluation of motions in real seas.Aiming at the evaluation of ship motions in real seas,firstly,a ship amplitude response database with small speed intervals was established using the strip method and 2.5D theory.Meanwhile,the interpolation method was used to construct the model that calculates the amplitude response of the ship at any speed.Secondly,based on the marine environment information simulated by the wave model and the amplitude response of the ship sailing,the evaluation model of ship motions in real seas was established by using the traditional spectrum analysis method.Besides,the software of ship motions evaluation was developed by Qt environment and verified by the ship motion data in real sea state.This paper combines mesoscale wind and wave prediction with ship motion forecasting,uses spectrum analysis methods to establish an evaluation model for ship motions in real seas.Meanwhile,it is preliminarily verified by using actual ship motion data.The research results of this paper can provide technical basis for the safety of ship navigation and route planning optimization.