CDT-SIS-155: Effects of multiscale roughness on turbulent flows

Majority of real-world surfaces develop natural irregularities. For example, ship hulls that have been fouled by patches of barnacles or corrosion or river beds where sediment has been deposited or has range of vegetation growth. The roughness of the surface will substantially alter the structure of the flow over that surface. Most previous studies have examined a flow over a rough surface by only considering surfaces with homogenous roughness (e.g. sandpaper) or with uniformly distributed cubes or cylinders. The objective of this project is to understand the effects of irregular multi-scale surface roughness, which is more representative of realistic surfaces, on the aerodynamics and hydrodynamics of the turbulent boundary layers formed near the surface.

A range of experiments will be performed in the wind tunnel and water channel facilities at the University of Southampton using multi-scale roughness patches that will be manufactured using the 3D-printing and laser cutting facilities at the University. Measurement techniques will include the use of a custom-built force balance, to directly measure the drag, and a suite of state-of-the-art laser-diagnostic equipment, such as particle image velocimetry (PIV), to measure the local flow structure, and planar laser-induced fluorescence (PLIF), to investigate the efficiency of the local scalar dispersion and mixing in the wake of the roughness patch.

The results of this work will have practical relevance to environmental, transportation, and energy engineering by setting the groundwork for the understanding and parameterization of multi-scale roughness effects on the dynamics of turbulent boundary layer flows.

If you wish to discuss any details of the project informally, please contact Dr Ganapathisubramani, Aerodynamics and Flight Mechanics research group, Email: [Email Address Removed] Tel: + 0044 (023) 8059 2305