Wall roughness

Motivation
Wall roughness is prevalent in many hydraulic and engineering flows. Factors such as manufacturing defects, harsh operating conditions, corrosion, and biomass accumulation over some time can cause walls that were initially smooth to become hydraulically rough. The presence of roughness can modify the mixing and turbulent transport phenomena of the flow. However, comprehensive investigations are required to better understand the impact of roughness in practical flows including separated and reattached flows, bluff-body aerodynamics, open channels and jets. Such research efforts will enable engineers and the research community to design more efficient and environmentally friendlier fluid-thermal systems.