Impacts of the source temperature and its distance on the statistical behavior of the convective air turbulence

Razi, Ebrahim Mohammadi; Rasouli, Saifollah

doi:10.1007/s00340-019-7296-7

Cited by 7 publications

(3 citation statements)

References 41 publications

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“…As shown in figure 1, two Cassegrain-Schmidt telescopes were used in experimental setup. It is worth mentioning that with the same arrangement, a pair of two-telescopic system, different turbulence conditions have been investigated [33,34]. In order to fix constant the diameter of the beam, as it propagates through the turbulent area, the output light from the first telescope is collimated.…”

Section: Governing Equations and Experimental Setupmentioning

confidence: 99%

Resilience of radial carpet beams under propagation through indoor convective air turbulence

Rasouli¹,

Bagheri²

2022

J. Opt.

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In this work, we investigate and compare propagation of Laguerre-Gaussian (LG) and the recently introduced Radial Carpet (RC) beams through an indoor convective air turbulence under weak to strong turbulence conditions. By determining the radial displacement of the intensity maxima over the donut ring of the LG beam, and tracing the radial coordinates of the main intensity spots of the RC beam, when the beams are propagating through the turbulence, we estimate the variance of the local displacements for both of the beams in the radial direction. It is shown that, under the same turbulence conditions, the RC beam experiences less disturbance and is more resilient to turbulence, especially when it has a complicated structure. The measured values of the image displacement variance for the RC beam are almost one order of magnitude smaller than the same parameter for the LG beam. In addition, for the LG beam, the symmetry of the beam is broken and in many places the intensity ring is even cut off. Although there are slight changes in the RC beams transverse intensity distribution, the number of the main intensity spots rarely changes. This feature makes the RC beam a good candidate for the transmission of information. We also show that a set of RC beams having different values of the main intensity spots (generated with different radial gratings having different spoke numbers) can be used as an orthogonal bases for free-space optical communication.

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Section: Governing Equations and Experimental Setupmentioning

confidence: 99%

Resilience of radial carpet beams under propagation through indoor convective air turbulence

Rasouli¹,

Bagheri²

2022

J. Opt.

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“…In this system, a fluid layer is heated from below and cooled from above. However in some studies the turbulent medium is only heated from below [12][13][14][15][16][17][18][19][20]. The effects of convective turbulence have been studied on the propagation of a light beam through convective air turbulence [12][13][14][15][16][17][18][19][20] and underwater [21][22][23][24][25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

“…However in some studies the turbulent medium is only heated from below [12][13][14][15][16][17][18][19][20]. The effects of convective turbulence have been studied on the propagation of a light beam through convective air turbulence [12][13][14][15][16][17][18][19][20] and underwater [21][22][23][24][25][26][27][28]. Bissonnette [21] and Gurvich et al [22] were among the pioneers in the studying of the optical properties of underwater convective turbulence.…”

Section: Introductionmentioning

confidence: 99%

Study of anisotropy of convective optical underwater turbulence and the effect of the mean water temperature in the presence of a varying temperature gradient on it

Razi¹,

Shokoohi²,

Rasouli³

2022

Laser Phys.

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In this paper, the anisotropy of optical convective underwater turbulence is investigated in terms of the variance of angle of arrival (AOA) fluctuations of a narrow laser beam propagating through it in different sections of the medium. The collimated laser beam with a wavelength 532 nm and a diameter 1 cm, which passes through a convective underwater turbulence. The turbulence is generated in a water tank with dimensions of 20 cm × 36 cm × 20 cm, which is installed on a flat surface electrical heater. During the experiments, the mean water temperature (MWT) can be changed from room temperature to 34 ∘C by increasing the heater temperature. The use of the heater also generates a temperature gradient in the medium. The laser beam propagates along a horizontal path with a length of 20 cm inside the tank at different altitudes from the heater source, as well as at different distances from one of the side walls of the turbulent medium. After passing the laser beam through the turbulent medium, the fluctuations of the AOA components in the vertical and horizontal directions are measured. From the time series of the measured AOA fluctuations, their variances are determined. The anisotropy of the medium is investigated by comparing the variance of AOA components measured in the vertical and horizontal directions. We show that the variances of both of vertical and horizontal components of the AOA fluctuations are increased with the MWT, and they are saturated at higher MWTs. In addition, different anisotropic behaviors are observed for the variances of the measured AOA fluctuations at the vicinity of the lateral wall and upper surface of the water. At the vicinity of the lateral wall the variances of the AOA fluctuations in the horizontal component are larger, but at the vicinity of the upper surface the variances of the AOA fluctuations in the vertical component are dominant. This behavior may be caused by the change of the convection motion direction in the turbulent fluid.

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Research on the effect of thermal disturbance on temporal and spatial distributions of refractive index structure constant by moiré deflection tomography

Jiang,

Chen,

Cheng

et al. 2024

Appl. Phys. B

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Impacts of the source temperature and its distance on the statistical behavior of the convective air turbulence

Cited by 7 publications

References 41 publications

Resilience of radial carpet beams under propagation through indoor convective air turbulence

Resilience of radial carpet beams under propagation through indoor convective air turbulence

Study of anisotropy of convective optical underwater turbulence and the effect of the mean water temperature in the presence of a varying temperature gradient on it

Research on the effect of thermal disturbance on temporal and spatial distributions of refractive index structure constant by moiré deflection tomography

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