Research On Randomness Of Deepwater Ocean Environment And Its Application On Offshore Platform Simulation System

This research belongs to the national863research topic named“Offshore Platform Operation Simulation System” and based on the“SimulationSystemfor981OffshorePlatform”developedbyShanghai JiaoTong University. In this research, study around randomness change ofdeepwater ocean environment in simulation system has been done anddevelopment of simulation program has been finished.This dissertation first introduces the composition of ocean environment,then chooses the most important three environment components as researchand simulation subjects, i.e. the wind, the wave and the current in ocean. Asto each environment component, this dissertation first gives the simulationrequirement from simulation system, then designs simulation method, anddevelops simulation program using Matlab software. The work flow chartof each simulation program and the determination method for simulationparameters are also given in this dissertation.In wind velocity simulation part, chooses combined wind speed modelas basic model. Improves the basic combined wind speed model by addingspecial feature of ocean wind speed, which are wind speed changed bydifferent height and the wave condition factor. Gives a non-parametricmethod in the modeling of random wind component. As in wind directionpart, based on the characteristics in wind direction random change, this dissertation designs simulation method both for main wind direction perhour and instant wind direction. In simulation of3-D wave, after studyingon different wave simulation method, this research uses the simulationmethod based on wave spectrum. And provides variable frequency spectrumfunctions and direction extension functions in3-D wave simulation program.In current simulation part, simulation methods have been designed forcurrent velocity and current direction in the same water depth, and inmultiple water depths. In addition, this dissertation introduces simulation ofrapid current into current velocity simulation. At last, the final simulationprogram for the entire ocean environment is completed by combining all thesimulation programs for each single environment component.In the last part of this dissertation, simulation results of wind, wave andcurrent have been provided. The simulation results can be divided intoseveral groups by specific input parameters. According to the analysis ofsimulation results, we can find that both the computation speed andsimulation result are satisfactory. It proves that the simulation programreaches the demands of simulation system. And the simulation program hasbeen applied into simulation system successfully.