Numerical Simulation And Velocity Analysis Of Irregular Wave Generated Alongshore Current On A Plane Shore

Alongshore current is an important factor that causes sediment transport,shore evolution and pollutant transport.The causes include the action of wind,river to sea,wave and so on.This thesis only studies the alongshore current under irregular wave action,and numerical simulation is carried out for the alongshore current on different slopes of the shore.Through data analysis,we hope to use the slope of the shore and wave incident conditions to express the alongshore current intuitively.First,based on the MIKE21 PMS model,the parabolic mild slope equation is used to simulate the propagation of obliquely incident irregular waves,so the distribution law of wave height and wave radiation stress in the simulated area is obtained.Then the wave radiation stress is used as the input condition to simulate the alongshore current.The numerical simulation results are in good agreement with the experimental results of alongshore current physical models on the shore with the slope of 1/100 and 1/40.Second,change the slope of the shore,simulate the alongshore current on the shore with the slope of 1/20 and 1/10,then calculate the maximum velocity of the alongshore current together with the location of the maximum at different slopes and different wave incidence conditions.The relationship between the velocity distribution of the alongshore current and the slope of the shore as well as the wave incident condition is analyzed.Maps of the relationships between maximum current velocity as well as the location of the maximum and the incident conditions of waves at four shore slopes are given.Lastly,Gaussian distribution function is selected to fit the velocity distribution of alongshore current.The relationship between undetermined coefficient of Gaussian distribution function and shore slope as well as wave incident condition is determined based on statistical data.Then,the velocity distribution formula of alongshore current fitted by Gaussian distribution function is obtained for reference in practical engineering.