scholarly journals Counterflow quantum turbulence of He-II in a square channel: Numerical analysis with nonuniform flows of the normal fluid

2015 ◽  
Vol 91 (18) ◽  
Author(s):  
Satoshi Yui ◽  
Makoto Tsubota
Keyword(s):  
Numerical Analysis ◽  
Quantum Turbulence ◽  
Normal Fluid ◽  
Square Channel ◽  
Nonuniform Flows

scholarly journals A new self-consistent approach of quantum turbulence in superfluid helium

2020 ◽  
Vol 135 (7) ◽  
Author(s):  
Luca Galantucci ◽  
Andrew W. Baggaley ◽  
Carlo F. Barenghi ◽  
Giorgio Krstulovic
Keyword(s):  
Friction Force ◽  
Numerical Scheme ◽  
Quantum Turbulence ◽  
Navier Stokes ◽  
Superfluid Turbulence ◽  
Navier Stokes Equation ◽  
Normal Fluid ◽  
Vortex Lines ◽  
Self Consistent ◽  
Fully Coupled

AbstractWe present the Fully cOUpled loCAl model of sUperfLuid Turbulence (FOUCAULT) that describes the dynamics of finite temperature superfluids. The superfluid component is described by the vortex filament method while the normal fluid is governed by a modified Navier–Stokes equation. The superfluid vortex lines and normal fluid components are fully coupled in a self-consistent manner by the friction force, which induces local disturbances in the normal fluid in the vicinity of vortex lines. The main focus of this work is the numerical scheme for distributing the friction force to the mesh points where the normal fluid is defined (stemming from recent advances in the study of the interaction between a classical viscous fluid and small active particles) and for evaluating the velocity of the normal fluid on the Lagrangian discretisation points along the vortex lines. In particular, we show that if this numerical scheme is not careful enough, spurious results may occur. The new scheme which we propose to overcome these difficulties is based on physical principles. Finally, we apply the new method to the problem of the motion of a superfluid vortex ring in a stationary normal fluid and in a turbulent normal fluid.

scholarly journals Heat Transfer Potentiality and Flow Behavior in a Square Duct Fitted with Double-Inclined Baffles: A Numerical Analysis

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Amnart Boonloi ◽  
Withada Jedsadaratanachai
Keyword(s):  
Heat Transfer ◽  
Numerical Analysis ◽  
Numerical Models ◽  
Flow Behavior ◽  
Square Duct ◽  
Square Channel ◽  
Nusselt Numbers ◽  
Friction Factors ◽  
Commercial Code ◽  
Volume Method

Numerical analysis of heat transfer mechanisms and flow topologies for the heat exchanger square channel (HESC) installed with the double-inclined baffles (DIB) is reported. The main objective of the present research is to study the influences of DIB height to duct height ( b / H = 0.05 – 0.30 ), DIB distance to duct height ( P / H = 1 – 1.5 ), and flow attack angle ( α = 30 °   and   45 ° ) on the flow topologies, heat transfer features, and thermal performances. The Reynolds numbers (based on the entry HESC around 100–2000) are analyzed for the present problem. The numerical models of the HESC installed with the DIB are solved with finite volume method (commercial code). The simulated results of the HESC installed with the DIB are reported in forms of flow topologies and heat transfer characteristics. The Nusselt numbers (Nu), friction factors ( f ), and thermal enhancement factors (TEF) of the HESC placed with the DIB are offered. As the numerical results, it is seen that the DIB produces the vortex streams and impinging streams in all cases. The vortex streams and impinging streams disturb the thermal boundary layer on the HESC walls that is a key motive for the growth of heat transfer rate. The best TEF of the HESC installed with the DIB is about 3.87 at P / H = 1 , α = 30 ° , Re = 2000 , and b / H = 0.15 . Additionally, the TEF contours, which help to design the HESC inserted with the DIB, are performed.

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