Scaling behavior of the inert gas Brillouin spectra

Fookson, Jeffrey E.; Gornall, W. S.; Cohen, H. D.

doi:10.1063/1.432774

Cited by 7 publications

(5 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To avoid the effects of transport coefficients on the RBS-line shape their values are taken at fixed nominal values (κ = 2.55 × 10 −2 W/m•K, η s = 1.83 × 10 −5 Pa•s, and η b = 1.48 × 10 −5 Pa•s), even though these coefficients may be temperature dependent, or be subject to freezing out of internal relaxation modes. Fixing the values of these thermodynamic properties implies that they do not affect the dimensionsless or This universal scaling was investigated and tested for experimental RB-spectra of noble gases [8,10,11]. The scaling in those studies was done for constant scattering conditions (θ, λ i ), while combinations of gaseous settings (p, T ) were chosen as to match a similar value of y.…”

Section: Universal Scaling Of Rb-scattering In Airmentioning

confidence: 99%

“…In this context the shear viscosity η s is a parameter connected to the kinetics describing the molecular collisions in terms of a mean-free-path. Such scaling in terms of dimensionless parameters was discussed and tested for gases with atomic constituents [58][59][60]. The scaling is expected to hold for densities for which the Boltzmann equation may be applied, thus where the mean field or average interaction between molecules may be neglected.…”

Section: Universal Scaling Of Rb-scattering In Airmentioning

confidence: 99%

“…This demonstration of dimensionless scaling of calculated spectra verifies that spectra, recorded in one set of conditions can be transferred to another set of conditions. This universal scaling was investigated and tested for experimental RB-spectra of noble gases [58][59][60]. The scaling in those studies was done for constant scattering conditions (θ , λ i ), while combinations of gaseous settings (p, T) were chosen as to match a similar value of y.…”

Section: Universal Scaling Of Rb-scattering In Airmentioning

confidence: 99%

See 2 more Smart Citations

Rayleigh-Brillouin light scattering spectroscopy of air; experiment, predictive model and dimensionless scaling

Wang

Liang

et al. 2020

Molecular Physics

View full text Add to dashboard Cite

Spontaneous Rayleigh-Brillouin scattering (RBS) experiments have been performed in air for pressures in the range 0.25-3 bar and temperatures in the range 273-333 K. The functional behaviour of the RB-spectral profile as a function of experimental parameters, such as the incident wavelength, scattering angle, pressure and temperature is analyzed, as well as the dependence on thermodynamic properties of the gas, as the shear viscosity, the thermal conductivity, the internal heat capacity and the bulk viscosity. Measurements are performed in a scattering geometry detecting at a scattering angle θ = 55.7 • and an incident wavelength of λi = 532.22 nm, at which the Brillouin features become more pronounced than in a right angles geometry and for ultraviolet light. For pressure conditions of 1-3 bar the RB-spectra, measured at high signal-to-noise ratio, are compared to Tenti-S6 model calculations and values for the bulk viscosity of air are extracted. Values of η b are found to exhibit a linear dependence on temperature over the measurement interval in the range 1.0 − 2.0 × 10 −5 Pa•s. A temperature dependent value is deduced from a collection of experiments to yield: η b = (0.86 × 10 −5) + 1.29 × 10 −7 • (T − 250). These results are implemented in model calculations that were verified for the low pressure conditions (p < 1 bar) relevant for the Earth's atmosphere. As a result we demonstrate that the RB-scattering spectral profiles for air under sub-atmospheric conditions can be generated via the Tenti-S6 model, for given gas-phase and detection conditions (p, T , λi, and θ), and for values for the gas transport coefficients. Spectral profiles for coherent RB-scattering in air are also computed, based on the Tenti-S6 formalism, and the predictions are compared with profiles of spontaneous RBS. Finally data on RB-scattering in air, obtained under a variety of pressure, temperature, wavelength and scattering angles, are analyzed in terms of universal scaling, involving the dimensionless uniformity parameter y and the dimensionless frequency x. Such scaling behaviour is shown to be well behaved for a wide parameter space and implies that RB-scattering spectra can be generated for a wide range of atmospheric applications of RB-scattering. The verification of this dimensionless scaling also shows that air can be treated as an ideal gas in the atmospheric regime, where y ≤ 1.

show abstract

Section: Universal Scaling Of Rb-scattering In Airmentioning

confidence: 99%

Section: Universal Scaling Of Rb-scattering In Airmentioning

confidence: 99%

Section: Universal Scaling Of Rb-scattering In Airmentioning

confidence: 99%

See 1 more Smart Citation

Rayleigh-Brillouin light scattering spectroscopy of air; experiment, predictive model and dimensionless scaling

Wang

Liang

et al. 2020

Molecular Physics

View full text Add to dashboard Cite

show abstract

“…In approximate expression (120), the first three terms represent the Lorentzian Rayleigh and Brillouin peaks and the last two terms give a fairly small, but not negligible, non-Lorentzian contribution. Next, as in Clark [7] and Fookson et al [13], let us define a dimensionless angular frequency,…”

Section: Light Scatteringmentioning

confidence: 99%

“…Previous experimenters, e.g. Clark [7] and Fookson et al [13], did not study gases fully in the hydrodynamic regime, Kn O 10 −2 , choosing instead to focus on more rarefied gases with Knudsen numbers in the range, O 10 −1 Kn O (1), which extends into the slip flow and transition regimes. Therefore, in order to verify the M (D, η)-formulation, it is important to conduct a high-resolution light scattering experiment for a gas in the hydrodynamic regime.…”

Section: Introductionmentioning

confidence: 99%

A New Continuum Formulation for Materials--Part II. Some Applications in Fluid Mechanics

Morris

2017

Preprint

View full text Add to dashboard Cite

In part I of this paper, I proposed a new set of equations, which I refer to as the M (D, η)-formulation and which differs from the Navier-Stokes-Fourier description of fluid motion. Here, I use these equations to model several classic examples in fluid mechanics, with the intention of providing a general sense of comparison between the two approaches. A few broad facts emerge: (1) it is as simple-or in most cases, much simpler-to find solutions with the M (D, η)-formulation, (2) for some examples, there is not much of a difference in predictions-in fact, for sound propagation and for examples in which there is only a rotational part of the velocity, my transport coefficients D and η are chosen to match Navier-Stokes-Fourier solutions in the appropriate regimes, (3) there are, however, examples in which pronounced differences in predictions appear, such as light scattering, and (4) there arise, moreover, important conceptual differences, as seen in examples like sound at a non-infinite impedance boundary, thermophoresis, and gravity's effect on the atmosphere.

show abstract

Density fluctuations in a dilute gas of Lennard-Jones molecules

Ranganathan

Yip

1979

The Journal of Chemical Physics

View full text Add to dashboard Cite

Scaling behavior of the inert gas Brillouin spectra

Cited by 7 publications

References 12 publications

Rayleigh-Brillouin light scattering spectroscopy of air; experiment, predictive model and dimensionless scaling

Rayleigh-Brillouin light scattering spectroscopy of air; experiment, predictive model and dimensionless scaling

A New Continuum Formulation for Materials--Part II. Some Applications in Fluid Mechanics

Density fluctuations in a dilute gas of Lennard-Jones molecules

Contact Info

Product

Resources

About