The effect of localized roughness on a Ma=4.8 boundary-layer and its instability is investigated by means of unsteady direct numerical simulations. The occurrence of special flow features, such as shocks, boundary-layer separation zones, streamwise vortices and streamwise streaks behind a three-dimensional square-shaped roughness element are discussed. In order to investigate the convective ins...

The effect of ice crystal surface roughness on light scattering by ice crystals which are large compared to the wavelength was studied, in particular changes to the 2D scattering patterns, azimuthally averaged phase functions, degree of linear polarisation patterns and asymmetry parameters for a range of orientations and roughness scales. It was found that roughness has an effect on light scatt...

in magnetic abrasive finishing (maf), abrasive grains as a tool move on surface and can removechip from surface of work piece. in this study al 6061 tube was considered as the work piece andthe effect of finishing parameters such as gap distance between tube and poles, rotational speed oftube, abrasive ration and finishing time on surface roughness was investigated. the mixture offerromagnetic ...

In Pawlak’s rough set theory, a set is approximated by a pair of lower and upper approximations. To measure numerically the roughness of an approximation, Pawlak introduced a quantitative measure of roughness by using the ratio of the cardinalities of the lower and upper approximations. Although the roughness measure is effective, it has the drawback of not being strictly monotonic with respect...

Modern wind turbines usually suffer unexpected power losses after long operating periods due to the contaminations accumulated at the leading edge of blades. In order to investigate the underlying physics, experiments were conducted to study the performance degradation of low-Reynolds-number airfoils induced by distributed leading edge roughness. Roughness was simulated by precisely manufacture...

Surface roughness (texture) has an effect on fluid flow in networks which has been studied for well over a century. The exact effect roughness has on fluid flow has not been completely understood, but a working estimate has been offered by a variety of authors over time. The work of Colebrook, Nikuradse, and Moody has provided practitioners with a method to include at least a first order estima...

surfaces may have the same roughness index but one surface may have the roughness on average spaced farThe measurement of the roughness of soil surfaces on centimeter ther apart on the surface. A more complete characterizascales is important to modeling local soil erodibility. An acoustic backscatter technique was examined for its ability to quantify the tion would describe not only vertical sc...

In this paper we present an investigation into visually perceived surface roughness. First we present psychophysical evidence that suggests that there is a simple relationship between perceived roughness and two well known surface parameters: fractal dimension and rms roughness. And that neither are good estimators, on there own, of perceived roughness. Second we present a measurement model for...

background: an increase in surface roughness of ceramics may decrease strength and affect the clinical success of ceramic restorations. however, little is known about the effect of acidic agents on ceramic restorations. the aim of this study was to evaluate the surface roughness of dental ceramics after being immersed in acidic agents.     methods: eighty-three ceramic disk specimens (12.0 mm i...