DNS of a lower curved wall channel: turbulent separation

Direct numerical simulations (DNS) are carried out to study turbulence dynamics in the separation bubble in lower curved wall channels. Boundary layer separation consists of fluid flow around bodies becoming detached, which causes the fluid closest to the object’s surface to flow in reverse or different directions, most often giving rise to turbulent flow. The study of turbulence and boundary layer separation has long been of interest to many scientists [1], but despite its importance, this classic subject is still incompletely explored in turbulent conditions, and is especially challenging for numerical simulations. The separation of fluid flow from objects inevitably results in effects such as drag, increased mixing, momentum and energy transfer and vortex shedding. For instance, an understanding of such effects is helpful to improve road vehicle performance, in the study of structure-fluid interactions, to regulate air mixing with other substances e.g. pollutants or in the study of boundary layer control [2, 3] which is a large area of interest to researches ranging from classical technological applications up to bioengineering such as in hemodynamics, where a decrease in blood vessel section may be induced by the local degeneration of the arterial wall (atherosclerosis).