Atmospheric turbulence

In this study, we suggested an FSO system with RIS assistance to mitigate the effects of signal blockage in the communication system, atmospheric turbulence, and UAV’s misalignment-induced fading. In a free-space environment with obstacles, the probability density function and cumulative distribution functions of an FSO system made up of RIS are derived.

8p vithomson 02-07-2024 0 0   Download

Ebook "Terrestrial biosphere-atmosphere fluxes" provide the tools to understand and quantitatively analyse fluxes of energy, organic compounds such as terpenes, and trace gases including carbon dioxide, water vapour and methane. It first introduces the fundamental principles affecting the supply and demand for trace gas exchange at the leaf and soil scales: thermodynamics, diffusion, turbulence and physiology.

519p duongthandue0501 28-02-2024 6 1   Download

Ebook "Adaptive beaming and imaging in the turbulent atmosphere" due to the wide application of adaptive optical systems, an understanding of optical wave propagation in randomly inhomogeneous media has become essential, and several numerical models of individual AOS components and of efficient correction algorithms have been developed. This monograph contains detailed descriptions of the mathematical experiments that were designed and carried out during more than a decade's worth of research.

211p nhanphanguyet 28-01-2024 4 2   Download

Part 2 book "Wavelets in physics" includes content: Wavelets and detection of coherent structures in fluid turbulence; wavelets, non linearity and turbulence in fusion plasmas; transfers and fluxes of wind kinetic energy between orthogonal wavelet components during atmospheric blocking; wavelets in atomic physics and in solid state physics; the thermodynamics of fractals revisited with wavelets; wavelets in medicine and physiology; wavelet dimensions and time evolution.

254p muasambanhan05 22-01-2024 4 2   Download

Ebook "Smoke, dust, and haze: Fundamentals of aerosol dynamics" covers the effects of turbulence on coagulation and gas-to-particle conversion and also discusses the formation of primary particles by the collision-coalescence mechanism. The chapter on the atmospheric aerosol has been completely rewritten within the aerosol dynamics framework. Its basic approach and topicality make Smoke, Dust, and Haze: Fundamentals of Aerosol Dynamics, 2/e, an essential guide for both students and researchers.

431p loivantrinh 29-10-2023 6 3   Download

This work investigates a system availability of high-altitude platform station (HAPS)-based free-space optical (FSO) system based on the observed cloud data from the European Center for Medium-Range Weather Forecast (ECMWF).

6p viannee 02-08-2023 7 4   Download

An approximate method is proposed for determining the aerodynamic effect of coherent vortex structures (CVS) of atmospheric turbulence on an aircraft. As a source of the CVS the vortex wind wakes arising when the atmospheric wind flows around the mountain massif of the Son Tra peninsula, located near the Da Nang airport, and the vortex wake behind the Su-27 type aircraft in the landing configuration are considered.

20p viwolverine 11-07-2023 9 2   Download

This paper presents the theoretical analysis of the average symbol error rate (ASER) of free space optical (FSO) communication system combined with multiple-input multiple-output (MIMO) relay based on Amplify-and-Forward (AF) technique employing subcarrier quadrature amplitude modulation (SC-QAM) signal over strong atmospheric turbulence, which is modeled by Gamma-Gamma distributions and pointing error.

5p vijaguar 16-11-2022 4 1   Download

This paper presents the theoretical analysis of misalignment fading effects on performance of free-space optical (FSO) communication system based on Amplify-and-Forward (AF) relaying technology. This system uses subcarrier quadrature amplitude modulation (SC-QAM) over weak atmospheric turbulence modelled by Log-Normal distribution.

5p vispyker 16-11-2022 13 3   Download

A finite-volume code is developed to compute the turbulent airflow over small-scale complex terrain. A pressure-correction algorithm is ·used to solve the threedimensional non-hydrostatic flow equations. The turbulent transport is simulated by the k- E: model using some modifications suitable for atmospheric boundary-layer application.

14p chikychiky 26-10-2018 22 0   Download

After its emission or secondary formation, the length of time airborne matter will remain suspended in the air will depend upon its density, shape and size and meteorological conditions. Suspended particles are deposited by dry deposition, either by sedimentation and gravitational settling or impaction due to atmospheric turbulence and diffusion. This latter process is characteristic of particles which undergo Brownian movement and sizes below 0.1µm.

318p saimatkhauroi 01-02-2013 52 6   Download

Computational Fluid Dynamics, broadly encompassing fluid flows in engineering, atmospheric and ocean sciences, geophysics, physics and astrophysics, has seen calculations of great fidelity performed routinely that were only imagined at the inception of this conference series in 1989. These advances have not only been made with the available horsepower of increasingly more powerful parallel computers, but in tandem with advances in implementations of core and of entirely new algorithms, including multi-scale and adaptive methods....

0p bachduong1311 07-12-2012 54 1   Download

The study of the formation and early evolution of stars has been an ever growing part of astrophysical research. Traditionally, often in the shadow of its big brothers (i.e., the study of stellar structure, stellar atmospheres and the structure of galaxies), it has become evident that early stellar evolution research contributes essentially to these classical fields. There are a few new items on the list of traditional astrophysical studies, some of which are more related to features known from the extreme late stages of stellar evolution.

409p tom_123 14-11-2012 55 10   Download

Advances in adaptive optics technology and applications move forward at a rapid pace. The basic idea of wavefront compensation in real-time has been around since the mid 1970s. The first widely used application of adaptive optics was for compensating atmospheric turbulence effects in astronomical imaging and laser beam propagation. While some topics have been researched and reported for years, even decades, new applications and advances in the supporting technologies occur almost daily.

266p cucdai_1 16-10-2012 48 7   Download

Estimating the transport and fate of chemicals released into the environment is an interesting and challenging task. The global environment is large on the chemical transport and fate scale. This text applies the mathematics of diffusion, turbulent diffusion, and dispersion to the atmosphere, lakes, rivers, groundwater, and oceans, as well as transport between these media. The book follows a new educational paradigm of textbooks, in that it is based on examples and case studies.

295p nhulan0908 29-09-2012 82 22   Download

The next chapter describes how a conventional model of ocean-atmosphere interaction can be modified to include the free convection within the air and the swell of the ocean. These effects become particularly important for low wind velocities, where the standard Charnock wind stress formula leads to a singularity. The article should be of particular interest to readers who are familiar with standard turbulence modeling, and it is important to weather modeling.

168p contentnew 12-04-2012 164 21   Download

Digital images and video, acquired by still cameras, consumer camcorders, or even broadcast-quality video cameras, are usually degraded by some amount of blur and noise. In addition, most electronic camerashavelimitedspatial resolutiondeterminedbythecharacteristicsof thesensorarray. Common causes of blur are out-of-focus, relative motion, and atmospheric turbulence. Noise sources include filmgrain, thermal, electronic, and quantization noise.

21p longmontran 18-01-2010 79 7   Download