the manning roughness coefficient is an important parameter in the design and evaluation of furrow irrigation. despite its importance, estimation of this parameter for surface irrigation is very difficult, particularly in furrow irrigation. in this study, an evalue model was used to estimate the manning roughness coefficient in furrow irrigation. the model was based on volume balance and develo...

The Visible Infrared Imaging Radiometer Suite (VIIRS) onboard Suomi National Polar Orbiting Partnership (SNPP) uses a solar diffuser (SD) as its radiometric calibrator for the reflective solar band calibration. The SD is made of SpectralonTM (one type of fluoropolymer) and was chosen because of its controlled reflectance in the Visible/Near-Infrared/Shortwave-Infrared region and its near-Lamber...

One of the surface energy balance components, the sensible heat flux, can easily be described for modelling and remote sensing purposes by means of the thermal roughness length (zot). This roughness length is usually expressed relative to the roughness length for wind speed (zou): kB−1 = ln(zou/zot). In the past, the kB−1 factor has been taken as a constant having a value of ca. 2 in the case o...

This paper reports on the effect of random Gaussian roughness with rms roughness values of 5-20 microm on the terahertz reflection spectra of metallic aluminum surfaces using Fourier transform IR spectroscopy. By comparing experimental data with a theoretical model based on the Kirchhoff approximation, the rms roughness of a surface is accurately determined. The rms roughness determined by this...

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...