The near-wall region of highly turbulent Taylor-Couette flow
Reads0
Chats0
TLDR
In this article, a simulation of the Taylor-Couette (TC) problem with mild curvature was performed, and the results showed that small-gap TC is dominated by spatially fixed large-scale structures known as Taylor rolls (TRs).Abstract:
Direct numerical simulations of the Taylor-Couette (TC) problem, the flow between two coaxial and independently rotating cylinders, have been performed. The study focuses on TC flow with mild curvature (small gap) with a radius ratio of $\eta=r_i/r_o=0.909$, an aspect ratio of $\Gamma=L/d=2\pi/3$, and a stationary outer cylinder. Three inner cylinder Reynolds of $1\cdot10^5$, $2\cdot10^5$ and $3\cdot 10^5$ were simulated, corresponding to frictional Reynolds numbers between $Re_\tau\approx 1400$ and $Re_\tau \approx 4000$. An additional case with a large gap, $\eta=0.5$ and driving of $Re=2\cdot10^5$ was also performed. Small-gap TC was found to be dominated by spatially-fixed large-scale structures, known as Taylor rolls (TRs). TRs are attached to the boundary layer, and are active, i.e. they transport angular velocity through Reynolds stresses. An additional simulation with inner cylinder Reynolds number of $Re=1\cdot10^5$ and fixed outer cylinder with an externally imposed axial flow of comparable strength as the wind of the TRs was also conducted. The axial flow was found to convect the TRs without any weakening effect. For small-gap TC, evidence for the existence of logarithmic velocity fluctuations, and of an overlap layer, in which the velocity fluctuations collapse in outer units, was found. Profiles consistent with a logarithmic dependence were also found for the angular velocity in large-gap TC, albeit in a very reduced range of scales. Finally, the behaviour of both small- and large-gap TC was compared to other canonical flows. Small-gap TC has similar behaviour in the near-wall region to other canonical flows, while large-gap TC displays very different behaviour.read more
Citations
More filters
Journal ArticleDOI
AFiD-GPU: A versatile Navier–Stokes solver for wall-bounded turbulent flows on GPU clusters
Xiaojue Zhu,Everett Phillips,Vamsi Spandan,John Donners,Gregory Ruetsch,Joshua Romero,Rodolfo Ostilla-Mónico,Rodolfo Ostilla-Mónico,Yantao Yang,Detlef Lohse,Roberto Verzicco,Massimiliano Fatica,Richard J. A. M. Stevens +12 more
TL;DR: The AFiD code, an open source solver for the incompressible Navier–Stokes equations, has been ported to GPU clusters to tackle large-scale wall-bounded turbulent flow simulations and the results are in excellent agreement with the experimental and computational data.
Journal ArticleDOI
A FFT-based finite-difference solver for massively-parallel direct numerical simulations of turbulent flows
TL;DR: An efficient solver for massively-parallel direct numerical simulations of incompressible turbulent flows using a second-order, finite-volume pressure-correction scheme, where the pressure Poisson equation is solved with the method of eigenfunction expansions.
Journal ArticleDOI
Taylor–Couette turbulence at radius ratio η=0.5: scaling, flow structures and plumes
Roeland C. A. van der Veen,Sander G. Huisman,Sebastian Merbold,Uwe Harlander,Christoph Egbers,Detlef Lohse,Chao Sun +6 more
TL;DR: In this article, high-resolution particle image velocimetry was used to measure velocity profiles, the wind Reynolds number and characteristics of turbulent plumes in Taylor-Couette flow for a radius ratio of 0.5 and Taylor number of up to 6:2 109.
Journal Article
Wall roughness induces asymptotic ultimate turbulence
Journal ArticleDOI
The effect of roll number on the statistics of turbulent Taylor-Couette flow
TL;DR: A series of direct numerical simulations in large computational domains has been performed in order to probe the spatial feature robustness of the Taylor rolls in turbulent Taylor-Couette (TC) flow as discussed by the authors.
References
More filters
Journal ArticleDOI
Turbulence statistics in fully developed channel flow at low reynolds number
TL;DR: In this article, a direct numerical simulation of a turbulent channel flow is performed, where the unsteady Navier-Stokes equations are solved numerically at a Reynolds number of 3300, based on the mean centerline velocity and channel half-width, with about 4 million grid points.
Journal ArticleDOI
Heat transfer and large scale dynamics in turbulent Rayleigh-Bénard convection
TL;DR: In this article, the Nusselt number and the Reynolds number depend on the Rayleigh number Ra and the Prandtl number Pr, and the thicknesses of the thermal and the kinetic boundary layers scale with Ra and Pr.
Journal ArticleDOI
The Structure of Turbulent Shear Flow
TL;DR: The Structure of Turbulent Shear Flow by Dr. A.Townsend as mentioned in this paper is a well-known work in the field of fluid dynamics and has been used extensively in many applications.
Journal ArticleDOI
Scaling of the velocity fluctuations in turbulent channels up to Reτ=2003
Sergio Hoyas,Javier Jiménez +1 more
TL;DR: In this article, a new numerical simulation of a turbulent channel in a large box at Reτ=2003 is described and briefly compared with simulations at lower Reynolds numbers and with experiments.
Related Papers (5)
The stability of viscous flow between rotating concentric cylinders with an axial flow
R. C. DiPrima,Adir Pridor +1 more