[M-IS21] Geophysical fluid dynamics-Transfield approach to geoscience

[MIS21-P02] Emergence of longitudinal roll structures in horizontal convection under non-uniform heating

*Daisuke Noto^1,2, Yuji Tasaka¹, Takatoshi Yanagisawa³, Takehiro Miyagoshi³ (1.Hokkaido University, 2.University of Pennsylvania, 3.JAMSTEC)

Keywords:Horizontal convection, Stratified flow

Since a baroclinic adjustment induces a convective flow even with a presence of a weak horizontal temperature gradient, heat is exchanged horizontally resulting in a global circulating flow. This phenomenon is called horizontal convection, and it is one of the key phenomena present in natural systems as well as in industrial applications. In the case of horizontal convection under a stably stratified system, i.e., non-uniform heating/cooling from top/bottom, the convective flow is confined to a shallow region at the vicinity of the horizontal wall with the non-uniform temperature. Due to the shallow roll structure, strong shear is induced on the wall. Meanwhile, the downstream (longitudinal) flow is accompanied by a heated fluid, and it goes immediately beneath the cooler wall. These two effects yield formations of roll structures having axes in the longitudinal direction when the horizontal temperature gradient is sufficiently strong. A similar three-dimensional structure is often considered in a forced boundary condition, such as a condition with wind, and it is known as horizontal convective rolls. We study the details of the longitudinal roll structures that emerged spontaneously in horizontal convection confined in a rectangular box throughout laboratory experiments.