5:15 PM - 7:15 PM
[MIS16-P07] Numerical Experiment on the Vertical Structure of the Wave Boundary Layer under Strong Winds
In theoretical research, parameterizing wave breaking requires empirical values validated through observations. To deepen the understanding of fundamental processes in the wave boundary layer—such as wave dynamics, turbulent mixing, material transport, and air-sea fluxes—a LES (Large Eddy Simulation) capable of consistently reproducing fluid motion on both the air and water sides is essential. However, conventional LES models have limitations: those in civil and mechanical engineering fields are constrained by overly small spatiotemporal scales, while those in atmospheric and oceanic sciences cannot explicitly resolve wave breaking. This study develops a coupled system that integrates the Wave Energy Spectral (WES) model with an LES model employing a vertically stretched grid, ensuring continuity between the air and water phases while capturing interactions between turbulence and surface waves. In the LES model, a steady westerly wind is imposed at an altitude of 500 m on the air side, and the development of turbulence is reproduced in three dimensions with a horizontal resolution of 1 m. The statistically averaged 10-m wind speed is fed into the WES model to obtain an equilibrium state incorporating wave breaking and nonlinear interactions. Since the WES model does not resolve phase variations of surface waves, the shape of the air-water interface in the LES model is reconstructed using vertical pressure gradient boundary conditions, enabling the representation of turbulence and orbital motion associated with phase changes of surface waves on both the air and water sides. Additionally, the LES model incorporates the effects of Earth's rotation, allowing momentum input from the air side to be counteracted by Ekman flow in the water side. Furthermore, multiple tracers are introduced to simulate the generation of sea salt particles from wave crests, reproducing the dynamics of marine aerosols.