Dynamics of density fluctuations in a turbulent flow

Yacomotti, A. M.; Hennequin, Pascale; Honoré, Cyrille; Raimbault, Jean; Grésillon, D.

doi:10.1016/j.physd.2004.10.005

Cited by 1 publication

(2 citation statements)

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“…Two important parameters are generally used to quantify the level of turbulence-the turbulence kinetic energy (k) and the turbulence intensity (I v ). The turbulence kinetic energy measures the intensity of turbulence fluctuations and is defined as the sum of specific kinetic energies associated with fluctuating components of the velocities in three orthogonal directions [31,32]. Figure 5 shows the typical variation of turbulence kinetic energy as a function of distance from the window wall.…”

Section: Resultsmentioning

confidence: 99%

“…The local density fluctuations, which may or may not contribute to the average flow characteristics [24], however, randomly contribute to the instantaneous refractive index of the medium [33]. Yokomotti et al [31] showed, through an optical technique, that large density fluctuations were clustered in an isotropic, homogeneous and subsonic air jet flow (Reynolds number ∼ 10 000, Mach number ∼ 0.02, at 0.5 bar). They also observed that the clusters resemble an oscillatory dynamics and the segments of oscillations were separated by more irregular behavior.…”

Section: Resultsmentioning

confidence: 99%

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A study of flow characteristics of a high repetition rate dye laser gain medium

Singh¹,

Kumar²,

Vora³

2014

Laser Phys.

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The gain medium of a high repetition rate liquid dye laser is made to flow at a sufficiently high velocity through the dye cell in order to minimize the thermal inhomogeneity. In this paper, temperature contours as a function of distance from the pump beam entrance dye cell window wall at various flow velocities in the laminar and turbulent region of gain medium flow were evaluated using computational fluid dynamics (CFD). Appreciable temperature gradients subsist at low Reynolds numbers due to inefficient heat transfer from the gain medium. However, at high Reynolds numbers >6000, the substantial effects of local density turbulent fluctuations degrade the optical quality of the gain medium. These computational studies were used to elucidate the characteristics of observed spectral fluctuations of a dye laser as a function of the Reynolds number.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%