Quantum turbulence

1986 ◽  
Vol 173 ◽  
pp. 387-429 ◽  
Author(s):  
Russell J. Donnelly ◽  
Charles E. Swanson
Keyword(s):  
Turbulent Flows ◽  
Quantum Turbulence ◽  
Fluid Model ◽  
Friction Theory ◽  
Vortex Lines ◽  
Open Questions ◽  
Simple Scaling ◽  
Two Fluid Model ◽  
Two Fluid ◽  
Scaling Arguments

We present a review of quantum turbulence, that is, the turbulent motion of quantized vortex lines in superfluid helium. Our discussion concentrates on the turbulence produced by steady, uniform heat flow in a pipe, but touches on other turbulent flows as well. We have attempted to motivate the study of quantum turbulence and discuss briefly its connection with classical turbulence. We include background on the two-fluid model and mutual friction theory, examples of modern experimental techniques, and a brief survey of the phenomenology. We discuss the important recent insights that vortex dynamics has provided to the understanding of quantum turbulence, from simple scaling arguments to detailed numerical simulations. We conclude with a discussion of open questions in this field.

A two-fluid model for gas-particle turbulent flows based on the probability density function approach

2019 ◽  
Vol 30 (01) ◽  
pp. 1950008
Author(s):  
Lu Wang ◽  
Jiangrong Xu
Keyword(s):  
Probability Density Function ◽  
Probability Density ◽  
Density Function ◽  
Turbulent Flows ◽  
Present Model ◽  
Fluid Model ◽  
Navier Stokes ◽  
Turbulence Modulation ◽  
Two Fluid Model ◽  
Two Fluid

According to experimental observations, laden particles in turbulence may attenuate or augment the carrier phase turbulence. But until now, there are no widely recognized models for estimating the so-called turbulence modulation phenomenon. In this paper, a novel two-fluid model is proposed based on the probability density function (PDF) approach. The Reynolds stress equation of the present model contains both production and dissipation terms due to the presence of particles, the turbulence modulation phenomenon can be well explained with the new model. To further explore the two-fluid model, a comparative study on PDF and Reynolds-averaged approaches is carried on, the differences and relations between the present model and the classical two-fluid Reynolds averaged Navier–Stokes (RANS) model are analyzed in the paper. Theoretical and numerical analysis indicates that the proposed model shows particular promise for predicting particle-laden turbulent flows.

Lagrangian accelerations of particles in superfluid turbulence

2013 ◽  
Vol 717 ◽  
Author(s):  
M. La Mantia ◽  
D. Duda ◽  
M. Rotter ◽  
L. Skrbek
Keyword(s):  
Quantum Turbulence ◽  
Fluid Model ◽  
Quantized Vortices ◽  
Superfluid Turbulence ◽  
Thermal Counterflow ◽  
Length Scales ◽  
Order Of Magnitude ◽  
The Mean ◽  
Two Fluid Model ◽  
Two Fluid

AbstractQuantum turbulence in thermal counterflow of superfluid ${\text{} }^{4} \mathrm{He} $ is studied at length scales comparable to the mean distance $\ell $ between quantized vortices. The Lagrangian dynamics of solid deuterium particles, of radius ${R}_{p} $ about one order of magnitude smaller than $\ell $, is analysed in a planar section of the experimental volume by using the particle tracking velocimetry technique. We show that the average amplitude of the acceleration of the particles seems to increase as the temperature decreases and applied heat flux increases and this can be explained by exploiting the two-fluid model of superfluid ${\text{} }^{4} \mathrm{He} $. We also report that, at the probed length scales, the normalized distribution of the acceleration of the particles appears to follow an unexpected classical-like behaviour.

Comparing Turbulence Models for Swirling Flows

2021 ◽  
pp. 25-36
Author(s):  
F.Kh. Nazarov
Keyword(s):  
Turbulent Flows ◽  
Poiseuille Flow ◽  
Linear Models ◽  
Fluid Model ◽  
Turbulence Models ◽  
The Novel ◽  
Turbulent Fluid Flow ◽  
Taylor Couette ◽  
Two Fluid Model ◽  
Two Fluid

The paper considers a turbulent fluid flow in a rotating pipe, known as the Taylor --- Couette --- Poiseuille flow. Linear RANS models are not suitable for simulating this type of problems, since the turbulence in these flows is strongly anisotropic, which means that solving these problems requires models accounting for turbulence anisotropy. Modified linear models featuring corrections for flow rotations, such as the SARC model, make it possible to obtain satisfactory solutions. A new approach to turbulence problems has appeared recently. It allowed a novel two-fluid turbulence model to be created. What makes this model different is that it can describe strongly anisotropic turbulent flows; moreover, it is easy to implement numerically while not being computationally expensive. We compared the results of solving the Taylor --- Couette --- Poiseuille flow problem using the novel two-fluid model and the SARC model. The numerical investigation results obtained from the novel two-fluid model show a better agreement with the experimental data than the results provided by the SARC model

scholarly journals Natural modes of the two-fluid model of two-phase flow

2021 ◽  
Vol 33 (3) ◽  
pp. 033324
Author(s):  
Alejandro Clausse ◽  
Martín López de Bertodano
Keyword(s):  
Two Phase Flow ◽  
Fluid Model ◽  
Phase Flow ◽  
Two Phase ◽  
Natural Modes ◽  
Two Fluid Model ◽  
Two Fluid

Self-consistent hydrodynamic two-fluid model of vortex plasma

2021 ◽  
Vol 33 (3) ◽  
pp. 037116
Author(s):  
Victor L. Mironov
Keyword(s):  
Fluid Model ◽  
Self Consistent ◽  
Two Fluid Model ◽  
Two Fluid

scholarly journals Mathematical study on two-fluid model for flow of K–L fluid in a stenosed artery with porous wall

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
R. Ponalagusamy ◽  
Ramakrishna Manchi
Keyword(s):  
Theoretical Study ◽  
Fluid Model ◽  
Porous Wall ◽  
Governing Equations ◽  
Rate Of Increase ◽  
Special Cases ◽  
Stenosed Artery ◽  
Flow Through ◽  
Two Fluid Model ◽  
Two Fluid

AbstractThe present communication presents a theoretical study of blood flow through a stenotic artery with a porous wall comprising Brinkman and Darcy layers. The governing equations describing the flow subjected to the boundary conditions have been solved analytically under the low Reynolds number and mild stenosis assumptions. Some special cases of the problem are also presented mathematically. The significant effects of the rheology of blood and porous wall of the artery on physiological flow quantities have been investigated. The results reveal that the wall shear stress at the stenotic throat increases dramatically for the thinner porous wall (i.e. smaller values of the Brinkman and Darcy regions) and the rate of increase is found to be 18.46% while it decreases for the thicker porous wall (i.e. higher values of the Brinkman and Darcy regions) and the rate of decrease is found to be 10.21%. Further, the streamline pattern in the stenotic region has been plotted and discussed.

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