Statistics of phase singularity of a speckle field in atmospheric turbulence

2010 ◽  
Author(s):  
Ruizhong Rao
Keyword(s):  
Atmospheric Turbulence ◽  
Speckle Field ◽  
Phase Singularity

scholarly journals A method of generating a random optical field using the Karhunen-Loeve expansion to simulate atmospheric turbulence

2020 ◽  
Vol 44 (1) ◽  
pp. 53-59
Author(s):  
S.N. Khonina ◽  
S.G. Volotovskiy ◽  
M.S. Kirilenko
Keyword(s):  
Numerical Simulation ◽  
Correlation Function ◽  
Atmospheric Turbulence ◽  
Random Environment ◽  
Random Medium ◽  
Optical Field ◽  
Phase Singularity ◽  
Vortex Beams ◽  
Simulation Results ◽  
Random Field Generation

It is proposed to use the random field generation in the numerical simulation of the propagation of radiation through a random medium using method based on the Karhunen–Loeve expansion with various types of correlation operators to describe turbulence simulators. The properties of the calculated simulators of a random medium with a Gaussian correlation function were investigated in modeling the propagation of Laguerre-Gaussian vortex beams. The simulation results showed that an increase in the order of the optical vortex leads, as in the experiment, to lower stability of the phase singularity of the beams to random optical fluctuations. The similarity of the simulation results and the optical experiments indicates the promise of the proposed approach for the synthesis of random environment simulators.

Prediction of Atmospheric Turbulence Characteristics for Surface Boundary Layer using Empirical Spectral Methods

2020 ◽  
Author(s):  
Yagya Dutta Dwivedi ◽  
Vasishta Bhargava Nukala ◽  
Satya Prasad Maddula ◽  
Kiran Nair
Keyword(s):  
Boundary Layer ◽  
Time Series ◽  
Surface Roughness ◽  
Wind Speed ◽  
Atmospheric Turbulence ◽  
Surface Boundary ◽  
Low Frequencies ◽  
Surface Boundary Layer ◽  
Power Spectral ◽  
Mean Wind Speed

Abstract Atmospheric turbulence is an unsteady phenomenon found in nature and plays significance role in predicting natural events and life prediction of structures. In this work, turbulence in surface boundary layer has been studied through empirical methods. Computer simulation of Von Karman, Kaimal methods were evaluated for different surface roughness and for low (1%), medium (10%) and high (50%) turbulence intensities. Instantaneous values of one minute time series for longitudinal turbulent wind at mean wind speed of 12 m/s using both spectra showed strong correlation in validation trends. Influence of integral length scales on turbulence kinetic energy production at different heights is illustrated. Time series for mean wind speed of 12 m/s with surface roughness value of 0.05 m have shown that variance for longitudinal, lateral and vertical velocity components were different and found to be anisotropic. Wind speed power spectral density from Davenport and Simiu profiles have also been calculated at surface roughness of 0.05 m and compared with k−1 and k−3 slopes for Kolmogorov k−5/3 law in inertial sub-range and k−7 in viscous dissipation range. At high frequencies, logarithmic slope of Kolmogorov −5/3rd law agreed well with Davenport, Harris, Simiu and Solari spectra than at low frequencies.

Estimating Atmospheric Turbulence Parameters from the Envelopes of Radio Acoustic Signals

2001 ◽  
Vol 55 (8) ◽  
pp. 5
Author(s):  
V. M. Kartashov ◽  
V. A. Petrov ◽  
Ye. G. Proshkin ◽  
G. I. Sidorov
Keyword(s):  
Atmospheric Turbulence ◽  
Acoustic Signals ◽  
Turbulence Parameters

Numerical study of wake vortex decay and descent in homogeneous atmospheric turbulence

AIAA Journal ◽  
2000 ◽  
Vol 38 ◽  
pp. 643-656 ◽  
Author(s):  
Jongil Han ◽  
Yuh-Lang Lin ◽  
S. P. Arya ◽  
Fred H. Proctor
Keyword(s):  
Atmospheric Turbulence ◽  
Numerical Study ◽  
Wake Vortex

A striped pattern of snowfall and snow cover

1993 ◽  
Vol 18 ◽  
pp. 27-32
Author(s):  
Yasuaki Nohguchi ◽  
Takashi Ikarashi ◽  
Osamu Abe ◽  
Atsushi Sato
Keyword(s):  
Snow Cover ◽  
Atmospheric Turbulence ◽  
Layered Structure ◽  
Time Variation ◽  
Vertical Wall ◽  
Striped Pattern

A striped pattern can be seen by spraying ink on a vertical wall of a snow pit to observe the layered structure of a snow cover. This pattern is caused by variations of snowfall in time, particularly pauses in snowfall, and its structure is related to a kind of fractal. In this paper, we consider snowfall and snow cover from a viewpoint of fractals and show that the layered structure of snow cover is a record of fractals on atmospheric-turbulence phenomena through the time variation of snowfall.

Quasi-Wavelet Models for Atmospheric Turbulence

2002 ◽  
Author(s):  
George H. Goedecke ◽  
D. K. Wilson ◽  
Vladimir E. Ostashev ◽  
Harry J. Auvermann
Keyword(s):  
Atmospheric Turbulence
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