In the domain of electromagnetic wave propagation in the presence of rough surfaces, the Rayleigh roughness criterion is a widelyused means to estimate the degree of roughness of considered surface. In this paper, this Rayleigh roughness criterion is extended to the case of rough layers. Thus, it provides an interesting qualitative tool for estimating the degree of electromagnetic roughness of ...

Surface roughness has a huge impact on many important phenomena. The most important property of rough surfaces is the surface roughness power spectrum C(q). We present surface roughness power spectra of many surfaces of practical importance, obtained from the surface height profile measured using optical methods and the atomic force microscope. We show how the power spectrum determines the cont...

This paper presents an investigation for the electromagnetic scattering characteristic of the 2-D infinitely long target located above two-layered 1-D rough surfaces. A finite-difference time-domain (FDTD) approach is used in this study, and the uniaxial perfectly matched layer (UPML) medium is adopted for truncation of FDTD lattices, in which the finite-difference equations can be used for the...

Abstract In this paper the magnetostatic energy in a ferromagnetic thin film with two imperfect, rough surfaces has been calculated. It has been shown that the surface roughness gives in some cases a considerable contribution to an effective perpendicular anisotropy. Within the model assumed it has been proved that the value of magnetostatic energy and, as a consequence, the anisotropy in a thi...

In this paper, we consider the derivation of the modified Wenzel’s and Cassie’s equations for wetting phenomena on rough surfaces from a three-dimensional phase field model. We derive an effective boundary condition by asymptotic two-scale homogenization technique when the size of the roughness is small. The modified Wenzel’s and Cassie’s equations for the apparent contact angles on the rough s...

The main purpose of this paper is to develop the method of characteristic functions for calculating the detection characteristics in the case of the object surrounded by rough surfaces. This method is to be implemented in synthetic aperture radar (SAR) systems using optimal resolution algorithms. By applying the specified technique, the expressions have been obtained for the false alarm and cor...

Influence of initial surface roughness on friction and wear processes under fretting conditions was investigated experimentally. Rough surfaces (Ra=0.15-2.52 μm) were prepared on two materials: carbon alloy (AISI 1034) and titanium alloy (Ti-6Al-4V). Strong influence of initial surface roughness on friction and wear processes is reported for both tested materials. Lower coefficient of friction ...

to enhance the understanding of the impact of obstacle buildings on pollution transportationand dispersion in the atmospheric boundary layer, it is necessary to know the atmospheric flow characteristics over terrains. wind flow characteristics in a boundary layer over a step-shaped cliff topography model with rough and smooth surfaces were studied numerically using computational fluid dynamics ...

The paper is devoted to statistical analysis of rough surfaces and extraction of parameters of significance for modelling of friction between the surfaces. It is known that modern experimental techniques, e.g., techniques based on atomic-force microscopy (AFM) allow the researchers to describe the surface topography up to atomic scale resolution. However, to predict any tribological process one...

A systematic study into the effect of solid roughness on the slip boundary condition during shear flow is presented. Atomic roughness is modeled by varying the size and spacing between solid atoms at constant packing fraction while the interaction parameters and the thermodynamic state of the fluid are kept constant. It is shown that the fluid structure as manifest in the amplitude of the densi...