Phenomenological theory of rough-wall boundary layers
Keywords: Turbulence, Phenomenological Theory, Rough Wall, Boundary Layer
AbstractDue to the difficulty in modeling turbulence, most studies into turbulent flows are largely empirical, either numerically or experimentally. However, recent theoretical development using the concept of the turbulent eddy and energy spectrum, has lead to a model framework in which observed flow behavior can be explained by purely theoretical means. This so called phenomenological theory has so far been successfully applied to confined flows such as pipe or channel flow which are homogeneous in the streamwise direction. Here we consider a spatially developing flow, namely the flow over a rough wall, and we present the necessary modifications to the theory in order to accurately capture the downstream development of the skin friction. We are able to conclude that the phenomenological theory, which our work is based upon, is applicable to spatially developing flows if the correct growth of the largest length scale in the problem is known.