Effect of surface texture on skin-friction - Dr. Pourya Forooghi

We are going to have a seminar on 'Effect of surface texture on skin-friction' delivered by Dr. Pourya Forooghi, Institute of Fluid Mechanics (ISTM), Karlsruhe Institute of Technology (KIT).

Abstract is given below.

Date & Time: 2:00-2:30 PM, Monday 29th of August 2016
Venue: Room 816, Rankine Building




Rough walls are predominant in several applications ranging from flow in pipes and turbomachines to the atmospheric boundary layer. Yet  the most ground-breaking piece of research in this field arguably dates back to the sand roughness experiments of Nikuradse published in 1936. While it is generally believed that for most rough surfaces, skin friction increases with the roughness height, the exact influence of roughness texture on friction is not well understood,although it is known as a matter of fact that roughness samples with similar height but different textures can lead to 'equivalent sand roughness' values an order of magnitude apart. This lack of understanding makes 'a priori' prediction of skin friction, i.e. predictions merely based on surface geometry, impossible. The present research attempts to shed some insight into the problem using Direct Numerical Simulation of channel flows over several artificially generated roughness samples.

First published: 26 August 2016