Numerical Simulation Of Typhoon Wind Field Based On Spiral Trajectory

Typhoon is a destructive marine weather system,causing serious damage to maritime transport,coastal engineering and aquaculture,resulting in huge economic losses and even casualties.It is important to understand the typhoon disaster characteristics and to assess the typhoon risk accurately.The typhoon wind field model is an important part of the typhoon risk analysis model.Therefore,the high precision typhoon wind field model,for the effective assessment of typhoon risk,coastal engineering disaster prevention and mitigation,and the rational planning of coastal economic construction is of great significance.With the rapid development of China's economy,the typhoon process on the coastal areas of the disastrous impact on the regional economic development of the destruction gradually highlighted.In recent years,the study of typhoon wind field has made important progress,and the new requirements have been put forward for the simulation accuracy of typhoon field.In this paper,several gradient wind field models and moving wind fields are proposed,and the different gradient wind field models are used to calculate eight typhoons.By comparing with the measured wind speed,several kinds of gradient wind field models show better simulation results.The comparison indicates that Holland gradient wind field model matches well with the measurements and has better applicability than other models.However,due to the fact that the actual typhoon image is helix,the basic assumptions of the gradient wind field can not accurately describe the typhoon spiral trajectory flow field.The Holland gradient wind field model has some approximate.At the same time,in the Holland wind field model,there is a pressure profile parameter B,Holland pressure profile parameter B on the typhoon wind field model has an important impact on the simulation accuracy.At present,there are two ways to obtain parameter B,but there is no theoretical basis to determine the Chinese coastal area Holland parameter B.In order to provide a more accurate wind field model,this paper is based on the logarithmic spiral trajectory field model and the new method of solving Holland parameter B is discussed.The factors influencing parameter B are discussed,including maximum wind speed radius,sea surface drag coefficient,The thickness of the air surface layer and the latitude of the typhoon.The results show that Holland parameter B is negatively correlated with maximum wind speed radius,drag coefficient and latitude,and positively correlated with surface layer thickness.Finally,the parameters B value is used to simulate eight typhoons,and the measured wind speed is compared and analyzed by different B-value empirical formula and the formula based on the spiral trajectory field model.It is proved that the model of logarithmic spiral trajectory field model has good applicability.