NUMERICAL STUDY OF LEE WAVES CHARACTERISTICS IN THE OCEAN

This study discusses the characteristics of lee waves in a vertical ocean slice model. To analyse the characteristics, this study applies two different scenarios; the first scenario employs a vertical ocean slice model with a uniform depth of 100 m and a width of 500 m and the second scenario uses the same model but considering an undersea mountain having a width of 100 m and a height of 40 m. Simulations on motions of the waves are generated by using a numerical method. Both scenarios implement the same force, which is the sea level gradient force that is maintained until the end of simulation time. In order to observe the significance of Courant-Friedrichs-Lewy (CFL) condition, numerical experiments are conducted using two values of time step sizes, Delta t = 0.1 second, which is obtained based on the CFL and Delta t = 1 second, which is chosen outside the interval of CFL criterion. The results of the experiments show that applying different values of the time step sizes do not significantly affect the resulting waves for the first scenario while it gives different outputs for the second scenario. The results in the first scenario present that the currents move horizontally and their velocities speed up over time while the values of water densities do not change throughout the simulation time. In the second scenario, the horizontal and vertical currents continuously change causing disturbances to the densities. From Fast Fourier Transform analysis, it is obtained that at depths of the surface level to 60 m, the magnitudes of carrier waves in the second scenario is greater than the magnitude of the first scenario, while at depths of below 60 m, the magnitude of carrier waves from the first scenario is greater than the magnitude of the second scenario.