[A-CG47] 海洋と大気の波動・渦・循環の力学

[ACG47-07] Numerical study of turbulence production by nonbreaking surface waves

★Invited Papers

*藤原 泰¹ (1.神戸大学大学院海事科学研究科)

キーワード：海洋波、波と流れの相互作用、波解像数値シミュレーション

Ocean surface waves play a crucial role in generating upper ocean turbulence, which significantly influences sea surface temperature and air-sea interaction. Experimental and numerical studies have demonstrated that, even without breaking, waves can induce turbulence even in the absence of wind, highlighting the importance of mechanisms other than Langmuir circulations. Using a newly developed two-phase numerical model that allows free propagation of interfacial waves without external forcing, we investigate the role of air-water coupling in this process. Our results show that the presence of an air layer above the water enhances turbulence in the upper ocean compared to water-only simulations. Energy budget analysis reveals that significant energy dissipation occurs in the air-side viscous boundary layer, characterized by strong shear. This dissipation amplifies Eulerian streaming at the upper water layer, which intensifies turbulence and produces eddies aligned with the wave propagation direction. These features are consistent with a Craik-Leibovich type wave-averaged simulation, where the Eulerian streaming is driven by the "virtual wave stress" of Longuet-Higgins [1969], with modifications to account for enhanced wave attenuation due to the air-side boundary layer.