Effects of surface thermal forcing on stratified flow past an isolated obstacle

摘要: The present study investigates basic aspects of the flow a density-stratified fluid past three-dimensional obstacles for Froude number ~ 0(1) and iso­ lated surface thermal forcing representative diurnaUy varying mesoscale flows mountainous islands such as Hawaii. In order to minimize param­ eter space, we have excluded effects friction, rotation, nonuniform am­ bient flow, complexities realistic boundary layer ter­ rain. Through simple scaJing arguments, deduce that parameter t]* given number, provide crude estimates response range 77*. principal question addressed is what values 77* will transition occur from low-Froude-number regime, characterized by stagnation splitting lower upwind regime in which passes over rather than around obstacle. We show linear the­ ory captures tendency consistently with scaling arguments. To quantitative measures variability 77*, employ an efficient isentropic numerical code summarize results numerous simulations form diagram. re­ sult criterion heated blocked unblocked regime. illustrate relevance idealized natural example appHcations Hawaiian Archipelago. flows] controls thermally forced