P. M. Ligrani

TL;DR: Ligrani et al. as mentioned in this paper investigated the effects of surface roughness on turbulent boundary layers, transitional phenomena in curved channels, and innovative schemes for internal cooling and surface heat transfer augmentation, such as dimpled surfaces and swirl chambers, as well as a variety of gas turbine heat transfer and blade cooling problems.

TL;DR: In this article, structural properties of transitionally rough and fully rough turbulent boundary layers were measured in flows at different roughness Reynolds numbers developing over uniform spheres roughness, and they asymptotically approach fully rough behaviour as Rek increases, and smooth behaviour at low Rek Profiles of other Reynolds-stress tensor components, turbulence kinetic energy, turbulence-kinetic energy production, and the turbulencekinetic-energy dissipation are also given, along with appropriate scaling variables.

TL;DR: In this paper, the viscous sublayer of a flat-plate turbulent boundary layer in air, using single hot-wire sensors with lengths from 1-60 viscous length scales, was measured and it was shown that, at a given distance from the surface, the turbulence intensity, flatness factor, and skewness factor of the longitudinal velocity fluctuation are nearly independent of wire length when the latter is less than 20-25 times the viscoelastic length scale.

TL;DR: In this paper, the authors measured on and above a dimpled test surface placed on one wall of a channel, and the results were given for Reynolds numbers from about 600 to about 11,000 and ratios of air inlet stagnation temperature to surface temperature ranging from 0.78 to 0.94.

TL;DR: In this article, the authors described the instantaneous, dynamic and time-averaged characteristics of the vortex structures which are shed from the dimples placed on one wall of a channel.