Chapters authored
Nonlinear Interaction Between Vortex and Wave in Rotating Shallow Water
This chapter is primarily concerned with the generation of inertia‐gravity wave by vortical flows (spontaneous emission) in shallow water system on an f‐plane. Sound waves are generated from vortical flows (aeroacoustics). There are many theoretical and numerical works regarding this subject. A shallow water system is equivalent to a two‐dimensional adiabatic gas system, if the effect of Earth's rotation is negligibly small. Then gravity waves are analogous to sound waves. While it is widely known that the effect of the Earth's rotation suppresses inertia‐gravity wave radiation, there are few studies about spontaneous emission in rotating shallow water. Here, the generation of inertia‐gravity waves by unsteady vortical flows is investigated analytically and numerically as an extension of aeroacoustics. A background of this subject is introduced briefly and several recent works including new results are reviewed. Main findings are cyclone‐anticyclone asymmetry in spontaneous emission and a local maximum of intensity of gravity waves emitted from anticyclones at intermediate value of the Coriolis parameter f, which are caused by the source originating in the Coriolis acceleration. All different experimental settings show the similar results, suggesting the robustness of these features.
Part of the book: Vortex Structures in Fluid Dynamic Problems