Experimental study of the influence of the stabilizing properties 
of transitional layers on the turbulent mixing evolution

Kucherenko, Yu.A.; Balabin, S.I.; Ardashova, R.I.; Kozelkov, O.E.; Dulov, A.V.; Romanov, Iu. A.

doi:10.1017/s0263034603213124

Cited by 13 publications

(22 citation statements)

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“…This acceleration is provided through different mechanisms, such as compressed air to accelerate the liquid column above air (Lewis 1950), rubber tubing and steel wire (Emmons, Chang & Watson 1960), bungee cords (Ratafia 1973), compressed air (Cole & Tankin 1973) and a weight-pulley drop tower (Waddell, Niederhaus & Jacobs 2001). To obtain large accelerations, Read (1984) used rocket rig motors, Dimonte & Schneider (1996) used a linear electric motor, and Kucherenko et al (2003) used a high-pressure gas system. Other types of transient experiments were performed using the Earth's gravitational field.…”

Section: B Akula and D Ranjanmentioning

confidence: 99%

Dynamics of buoyancy-driven flows at moderately high Atwood numbers

Akula

Ranjan

2016

J. Fluid Mech.

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Simultaneous density and velocity turbulence statistics for Rayleigh-Taylor-driven flows at a moderately high Atwood number (A t ) of 0.73 ± 0.02 are obtained using a new convective type or statistically steady gas tunnel facility. Air and air-helium mixture are used as working fluids to create a density difference in this facility, with a thin splitter plate separating the two streams flowing parallel to each other at the same velocity (U = 3 m s −1 ). At the end of the splitter plate, the two miscible fluids are allowed to mix and the instability develops. Visualization and Mie-scattering techniques are used to obtain structure shape, volume fraction profile and mixing height growth information. Particle image velocimetry (PIV) and hot-wire techniques are used to measure planar and point-wise velocity statistics in the developing mixing layer. Asymmetry is evident in the flow field from the Mie-scattering images, with the spike side showing a more gradual decline in volume fraction than the bubble side. The spike side of the mixing layer grows 50 % faster than the bubble side. PIV is implemented for the first time in these moderately high-Atwood-number experiments (A t > 0.1) to obtain root-mean-square velocities, anisotropy tensor components and Reynolds stresses across the mixing layer. Overall, the turbulence statistics measured have shown different scaling compared to small-Atwood-number experiments. However, the total probability density functions for the velocities and turbulent mass fluxes exhibit behaviour similar to small-Atwood-number experiments. Conditional statistics reveal different values for turbulence statistics for spikes and bubbles, unlike small-Atwood-number experiments.

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Section: B Akula and D Ranjanmentioning

confidence: 99%

Dynamics of buoyancy-driven flows at moderately high Atwood numbers

Akula

Ranjan

2016

J. Fluid Mech.

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“…They obtained an approximate single-mode perturbation at the density interface by oscillating a paddle, and measured the growth of individual bubbles and spikes using high-speed photography. Other researchers have also used some type of accelerated tank containing miscible or immiscible fluids of different densities to investigate the growth of Rayleigh-Taylor instability-driven mixing layers (Ratafia 1973;Cole & Tankin 1973;Popil & Curzon 1979;Read 1984;Jacobs & Catton 1988;Kucherenko et al 1994Kucherenko et al , 1997Kucherenko et al , 2003aDimonte & Schneider 1996, Dimonte 1999Wilkinson 2004).…”

Section: Previous Experimental Investigations Of Rayleigh-taylor Instmentioning

confidence: 99%

“…Standard photographic techniques limited investigations to the quantification of the spatial growth of the mixing layer; measurements of the internal structure of the mixing layer, and the quantification of the degree of molecular mixing were not possible. An alternative to using standard photography is to measure mixing layer widths using x-ray radiography (Kucherenko et al 1997(Kucherenko et al , 2003a. Kucherenko et al (2003a) measured the growth of a miscible, turbulent Rayleigh-Taylor mixing layer for different sets of initial diffusion layer thicknesses and small-scale random perturbations.…”

Section: Previous Experimental Investigations Of Rayleigh-taylor Instmentioning

confidence: 99%

“…An alternative to using standard photography is to measure mixing layer widths using x-ray radiography (Kucherenko et al 1997(Kucherenko et al , 2003a. Kucherenko et al (2003a) measured the growth of a miscible, turbulent Rayleigh-Taylor mixing layer for different sets of initial diffusion layer thicknesses and small-scale random perturbations. Also, Kucherenko et al (2003b) used laser-induced fluorescence (LIF) to measure the distribution of fluid fragment sizes within an immiscible, Rayleigh-Taylor turbulent mixing layer.…”

Section: Previous Experimental Investigations Of Rayleigh-taylor Instmentioning

confidence: 99%

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Experimental characterization of initial conditions and spatio-temporal evolution of a small-Atwood-number Rayleigh–Taylor mixing layer

2006

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The initial multi-mode interfacial velocity and density perturbations present at the onset of a small-Atwood-number, incompressible, miscible Rayleigh–Taylor instability- driven mixing layer have been quantified using a combination of experimental techniques. The streamwise interfacial and spanwise interfacial perturbations were measured using high-resolution thermocouples and planar laser-induced fluorescence (PLIF), respectively. The initial multi-mode streamwise velocity perturbations at the two-fluid density interface were measured using particle-image velocimetry (PIV). It was found that the measured initial conditions describe an initially anisotropic state, in which the perturbations in the streamwise and spanwise directions are independent of one another. The evolution of various fluctuating velocity and density statistics, together with velocity and density variance spectra, were measured using PIV and high-resolution thermocouple data. The evolution of the velocity and density statistics is used to investigate the early-time evolution and the onset of strongly nonlinear, transitional dynamics within the mixing layer. The early-time evolution of the density and vertical velocity variance spectra indicate that velocity fluctuations are the dominant mechanism driving the instability development. The implications of the present experimental measurements on the initialization of Reynolds-averaged turbulent transport and mixing models and of direct and large-eddy simulations of Rayleigh–Taylor instability-induced turbulence are discussed.

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“…Although most earlier high Atwood number R-T experiments were with immiscible fluids, considerable effort now appears to be focused on miscible systems. In addition to the gas tunnel results noted previously (Banerjee & Andrews 2006), preliminary experiments using a variation on the RR (Roberts & Jacobs 2008), and high-pressure gas systems (Kucherenko et al 2003), along with novel approaches such as magnetorheological fluids (White et al 2004), are showing considerable promise, although further progress on the associated diagnostics is necessary to provide the much-needed measurements in this miscible regime.…”

Section: Discussionmentioning

confidence: 96%

Small Atwood number Rayleigh–Taylor experiments

Andrews

Dalziel

2010

Phil. Trans. R. Soc. A.

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Consideration is given to small Atwood number (non-dimensional density difference) experiments to investigate mixing driven by Rayleigh-Taylor (R-T) instability. The past 20 years have seen the development of novel experiments to investigate R-T mixing and, simultaneously, the advent of high-fidelity diagnostics. Indeed, the developments of experiments and diagnostics have gone hand in hand, and as a result modern R-T experiments rival the capabilities and research scope of shear-driven mixing experiments. Thus, research into the small Atwood number limit has made significant progress over the past 20 years, and has offered important insights into natural mixing processes as well as the general R-T problem. This review of small Atwood number experiments serves as an opportunity to discuss progress, and also to provoke thoughts about future high Atwood number designs and difficulties.

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Experimental study of the influence of the stabilizing properties of transitional layers on the turbulent mixing evolution

Cited by 13 publications

References 1 publication

Dynamics of buoyancy-driven flows at moderately high Atwood numbers

Dynamics of buoyancy-driven flows at moderately high Atwood numbers

Experimental characterization of initial conditions and spatio-temporal evolution of a small-Atwood-number Rayleigh–Taylor mixing layer

Small Atwood number Rayleigh–Taylor experiments

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