Direct numerical simulation of transitional boundary layer with a roughness

Abstract

The presence of protuberances in several flows on surfaces, for example, rivets, screws and gaskets, can influence the boundary layer by accelerating the transition from laminar flow to turbulent flow. This may be undesirable, since the turbulent flow must involve a frictional force greater than the laminar one. There are some aspects in this type of flow that are not well understood. The aim of this work is to study the influence of an isolated roughness on a boundary layer. It is hoped that this study is a step towards the understanding of what can happen in more complex cases. The nature of this study is computational, where will be used direct numerical simulation (DNS). The immersed boundary layer will be used to represent the roughness in the flow on the flat plate. The results will be performed based on instability theories and turbulence applied to shear layer. (AU)