Influence of roughness height distribution and surface anisotropy on turbulence over rough walls

Time: Thu 2019-04-04 10.30 - 11.30

Lecturer: Angela Busse (University of Glasgow)

Location: Faxén, Teknikringen 8

Abstract. Wall-bounded turbulence is affected by surface roughness if the roughness height is comparable to the viscous length scale of the flow. The fluid dynamical roughness effect is known to increase with the height of the roughness, but the influence of the roughness topography, i.e. the height distribution of the rough surface and the spatial distribution of its features, is still not fully understood. While historically fundamental investigations of rough-wall turbulent flows have focussed on regular forms of roughness, in recent years irregular rough surfaces with complex topographies representative of typical engineering roughness have received increased attention. In this talk, recent results from direct numerical simulations of turbulent flow over irregular rough surfaces will be presented. Both the influence of the height distribution, by comparing irregular pit-dominated to peak-dominated rough-wall turbulent flows, as well as the influence of surface anisotropy with respect to the mean flow will be discussed.