The Reynolds number dependence of turbulent channel flow over two irregular rough surfaces, based on scans of a graphite and a gritblasted surface, is studied by direct numerical simulation. The aim is to characterise the changes in the flow in the immediate vicinity of and within the rough surfaces, an area of the flow where it is difficult to obtain experimental measurements. The average roug...

The Si removal property achieved by a localized microwave hydrogen plasma was investigated. relationship between generation parameters (input power, H2 gas flow rate, and initial surface roughness) the (etching rate revealed. Stress relief of affected layer etching were also demonstrated. Moreover, this technique presents no etching-rate dependence on crystal plane orientation. Therefore, even ...

We consider the non-stationary three dimensional viscous flow in a bounded domain, with the lateral surface containing microscopic surface irregularities. Under the assumption of a smooth flow in the domain without roughness, we prove that there is a smooth solution to a problem with the rough boundary. In the papers by Jäger and Mikelić the friction law was obtained as a perturbation of the Po...

We report experimental evidence of an effect opposite to the "solidification" of small bubbles in liquid where the surface can become immobile. Namely, it is demonstrated that smooth solid spheres falling in a yield-stress fluid under the action of gravity can behave similar to drops. Particle tracking velocimetry was used to determine the shape of the yielded region around solid spherical part...

Calcium lactate crystals that sometimes form on Cheddar cheese surfaces are a significant expense to manufacturers. Researchers have identified several postmanufacture conditions such as storage temperature and packaging tightness that contribute to crystal formation. Anecdotal reports suggest that physical characteristics at the cheese surface, such as roughness, cracks, and irregularities, ma...

High-resolution particle image velocimetry measurements are made in the streamwise–wall-normal plane of a zero-pressure-gradient turbulent boundary layer over smooth and rough walls at Re 13000. The roughness considered herein is replicated from a surface scan of a turbine blade damaged by deposition of foreign materials and its topography is highly irregular and contains a broad range of topog...

A high-resolution nested model initialized with either smooth or synthetically generated rough topography is used to investigate the role of small-scale in modulating eddy scales northern South China Sea. It found that while adding leads negligible changes surface and their seasonal cycle, it significantly reduces bottom by about 30%–40%. This reduction mainly contributed three processes: wave ...