scholarly journals Detection of a Semi-Rough Target in Turbulent Atmosphere by an Electromagnetic Gaussian Schell-Model Beam

2019 ◽  
Vol 9 (14) ◽  
pp. 2790
Author(s):  
Xiaofei Li ◽  
Yuefeng Zhao ◽  
Xianlong Liu ◽  
Yangjian Cai
Keyword(s):  
Inverse Problem ◽  
Atmospheric Turbulence ◽  
Turbulent Atmosphere ◽  
Incident Beam ◽  
Radar System ◽  
Equivalent Model ◽  
Laser Radar ◽  
Beam Radius ◽  
Tensor Method ◽  
Set Up

The interaction of an electromagnetic Gaussian Schell-model beam with a semi-rough target located in atmospheric turbulence was studied by means of a tensor method, and the corresponding inverse problem was analyzed. The equivalent model was set up on the basis of a bistatic laser radar system and a rough target located in a turbulent atmosphere. Through mathematical deduction, we obtained detailed information about the parameters of the semi-rough target by measuring the beam radius, coherence radius of the incident beam and the polarization properties of the returned beam.

scholarly journals Behavior of the Central Intensity of Generalized Humbert-Gaussian Beams Against the Atmospheric Turbulence

2021 ◽  
Author(s):  
Naima Nossir ◽  
Latifa Dalil-Essakali ◽  
Abdelmajid Belafhal
Keyword(s):  
Atmospheric Turbulence ◽  
Intensity Distribution ◽  
Turbulent Atmosphere ◽  
Incident Beam ◽  
Paraxial Approximation ◽  
Gaussian Beams ◽  
Central Intensity ◽  
Fresnel Integral ◽  
Special Cases ◽  
Beam Parameters

Abstract Based on the generalized Huygens-Fresnel integral in the paraxial approximation and on the Rytov theory, the analytical expression of the axial intensity distribution for the Generalized Humbert-Gaussian beams (GHGBs) propagating through a turbulent atmosphere is derived in this work. The results for the special cases of GHGBs are deduced from our study and illustrated numerically. The influence of the turbulent strength and the incident beam parameters on the propagation of these beams in the atmospheric turbulence is investigated and discussed in detail.

A compact 3D imaging laser radar system using Geiger-mode APD arrays: system and measurements

2003 ◽  
Author(s):  
Richard M. Marino ◽  
Timothy Stephens ◽  
Robert E. Hatch ◽  
Joseph L. McLaughlin ◽  
James G. Mooney ◽  
...  
Keyword(s):  
3D Imaging ◽  
Radar System ◽  
Laser Radar ◽  
Geiger Mode

Laser radar system for obstacle avoidance

2005 ◽  
Author(s):  
Karlheinz Bers ◽  
Karl R. Schulz ◽  
Walter Armbruster
Keyword(s):  
Obstacle Avoidance ◽  
Radar System ◽  
Laser Radar

Research on Methods for Elastic Stiffness of Multi-Ribbed Slab Structure

2010 ◽  
Vol 97-101 ◽  
pp. 1736-1740
Author(s):  
Qi Zhang ◽  
Dong Bo Li ◽  
Qian Feng Yao ◽  
Dong Zhao
Keyword(s):  
Time History ◽  
Elastic Stiffness ◽  
Structural Effect ◽  
Time History Analysis ◽  
Equivalent Model ◽  
Test Results ◽  
History Analysis ◽  
Set Up

Considering the influence of the flange and rib column, the equivalent model of multi-ribbed slab is set up by the theory based on the strengthening isotropism fiber. This model is simple, highly precise and strongly applicable through comparing analyzing results with test results. Besides, the calculated formulate is set up on the basis of the whole structural effect and space work, which offers the prerequisite for elastic time history analysis of the structure.

Flight test of 2-μm diode-pumped laser radar system

1995 ◽  
Author(s):  
Thomas J. Kane ◽  
Jeffrey D. Kmetec ◽  
Thomas J. Wagener
Keyword(s):  
Flight Test ◽  
Radar System ◽  
Laser Radar ◽  
Diode Pumped

Use of Tracer Particles for Tracking Fluid Interfaces in Primary Cementing

2019 ◽  
Author(s):  
Amir Taheri ◽  
Jan David Ytrehus ◽  
Ali Taghipour ◽  
Bjørnar Lund ◽  
Alexandre Lavrov ◽  
...  
Keyword(s):  
Numerical Models ◽  
Secondary Flows ◽  
Equivalent Model ◽  
Fluid Interfaces ◽  
Element Analysis ◽  
Two Fluids ◽  
Tracer Particles ◽  
Narrow Side ◽  
Primary Cementing ◽  
Set Up

Abstract In this study, a new approach for detailed tracking of the interface between well fluid and cement by using particles is investigated. This can improve the quality of annular cementing of CO2 wells and thus the storage safety. For this purpose, the displacement mechanisms of Newtonian and non-Newtonian fluids in the annulus of vertical and inclined wells is investigated by using an experimental set-up with an eccentric annular geometry and by finite element analysis of an equivalent model with COMSOL Multiphysics solver. For more efficient displacement, the displacing fluid has a higher density than the displaced fluid, and the intermediate-buoyancy particles that reside at the interface between successive fluids are introduced into the models. Such particles must overcome strong secondary flows in order to travel with the interface. Particle motions are investigated in different experimental and numerical models, and their effectiveness is investigated. The experimental results confirm that while the particles with a size of 425–500 um are unable to overcome the secondary flows in eccentric vertical models and track the interface, they can be useful for tracking the interface between two fluids in an eccentric model with a small inclination to the narrow side. CFD analysis investigates this behavior with more details and shows the effects of some parameters on the particle motions.

Sign in / Sign up

Export Citation Format

Share Document