Convective flow organization over rough surfaces

• Applicant: Dr.-Ing. Kay Schäfer
• Subject Area: Fluid Mechanics
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 549151875

The current research project aims to establish a fundamental physical understanding of the flow organization in turbulent mixed convection flows, and in particular how rough surfaces can modify this convective flow organization. In mixed convection, both shear and buoyancy effects contribute to the momentum and heat transfer, and this type of convection is of great importance in many technical and environmental flows, such as in heat exchangers or in the atmospheric bound­ary layer. In these applications, rough surfaces often occur, and a better understanding and representation of their effects on mixed convection is a long­standing challenge in weather and cli­mate models. Rough surfaces can modify the interaction between buoyancy and shear effects, which then might alter the convective flow organization known from smooth wall mixed convection flows. The flow organization in turn has an influence on the distribution of air pollution and water vapour distribution, which, for example, is relevant for cloud formation processes. In order to provide insight into this phenomenon, the present proposal is devoted to quantifying the impact of rough surfaces on the flow organization of turbulent mixed convection flows. In this proposal, we investigate fundamental aspects of the effect of roughness on mixed convection using direct numerical simulations for turbulent channel flows and convective boundary layers, which represent canonical flow configuration for environmental and engineering applications, respectively.

• DFG Programme: WBP Position