Wind-Generated Waves in the Laboratory: Turbulent Flow Fields in Air and Water and Interfacial Stresses
Speaker 2
Yasunori Watanabe, Hokkaido University
Multiphase flows in breaking waves
Ocean wave motion, well approximated by irrotational and inviscid flow, rapidly changes into rotational turbulent flow when the waves break. Formations of the organized vortices, generated under breaking waves, cause various mechanical processes; local deformation and mixing of sea surfaces, entrapment of air bubbles, sediment suspension, which supports biological activities in a marine ecosystem through gas and heat transport and material convection. The entrained air bubbles contribute to disturbing the flow, dissipating wave energy, and generating sea spray during the degassing process. Full mechanisms of such complex multiphase turbulence evolving in breaking processes have not been understood. Progress in breaking wave research on interactions of wave-surface, sediments, bubbles, and foam with wave-induced turbulence will be introduced in the seminar.
Speaker 3
Umeda/Sota Nakajo, Osaka Metropolitan University
Preliminary Study for Overtopping Analysis under Strong Wind Conditions Using OpenFOAM
During storm events, overtopping caused by high waves can lead to flooding and other damage in areas behind coastal structures. Since such overtopping occurs under strong wind conditions such as typhoons, it is necessary to investigate the influence of wind on the overtopping process. In this study, we focus on OpenFOAM’s multiphase flow model to develop a computational fluid dynamics (CFD) model capable of analyzing overtopping phenomena under strong wind conditions. As an initial step toward model development, we evaluated the reproducibility of overtopping phenomena under no-wind conditions using OpenFOAM.Furthermore, we received wind-wave experimental data obtained in a wind-wave flume from Prof. Natsuki Mizutani of Osaka Sangyo University. Based on these data, we conducted wind wave simulations using OpenFOAM and compared the results with the experimental data to investigate whether the effects of wind on waves are appropriately reproduced in OpenFOAM.
Speaker 4
Tomoya Shimura, Kyoto University
Momentum transfer at the ocean surface in the high speed wind region
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