Drag Computation on Rough Surfaces Using a Homogenised Model

Geometry-resolved simulations of flow over rough walls are highly expensive due to the associated disparity of geometric scales. Effective or homogenised models are often employed to circumvent this problem. However, existing effective models are aimed mainly at predicting the interface slip velocity on flat interfaces aligned along one of the Cartesian coordinate directions. In a recent work, Sahaj and Sudhakar (Phys Fluids 29, 2017) proposed an effective model in the polar coordinate system and presented results for laminar flows over a rough circular cylinder. Moreover, they introduced two constitutive parameters, named as stress correction factors, for the computation of pressure- and viscous-drag components on rough surfaces. This paper provides additional results of this model and discusses its limitation.