Browsing by Subject "Reynolds number"
Now showing items 21-40 of 57
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Article
Large Eddy Simulation of near-bed pipelines in oscillatory flow
(2018)A series of unsteady, three-dimensional numerical simulations of the incompressible, oscillatory flow around a near-bed pipeline is presented. A flow at Reynolds number equal to Reαo=20,000 with respect to the oscillatory ...
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Article
Large-eddy simulations of the turbulent Hartmann flow close to the transitional regime
(2007)A series of large-eddy simulations (LES) of turbulent and transitional channel flows of a conductive fluid under the effect of a uniform magnetic field applied in the wall-normal direction, usually referred to as Hartmann ...
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Article
Large-eddy simulations of unidirectional water flow over dunes
(2009)The unidirectional, subcritical flow over fixed dunes is studied numerically using large-eddy simulation, while the immersed boundary method is implemented to incorporate the bed geometry. Results are presented for a typical ...
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Article
Magnetohydrodynamic turbulence at moderate magnetic Reynolds number
(2004)We consider the case of homogeneous turbulence in a conducting fluid that is exposed to a uniform external magnetic field at low to moderate magnetic Reynolds numbers (by moderate we mean here values as high as 20). When ...
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Article
MHD flow past a circular cylinder using the immersed boundary method
(2010)The immersed boundary method (IB hereafter) is an efficient numerical methodology for treating purely hydrodynamic flows in geometrically complicated flow-domains. Recently Grigoriadis et als. [1] proposed an extension of ...
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Article
New analytical solutions for weakly compressible Newtonian Poiseuille flows with pressure-dependent viscosity
(2016)Steady-state, isothermal, Poiseuille flows in straight channels and circular tubes of weakly compressible Newtonian fluids are considered. The major assumption is that both the mass density and the shear viscosity of the ...
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Conference Object
Numerical simulations of turbulent flow in an eccentric annulus of unit eccentricity
(TSFP-9, 2015)In this study, we perform Direct Numerical Simulations (DNS) of fully developed turbulent flows in eccentric annuli having different diameter ratios. Annuli of unit eccentricity, and diameter ratios of 0.2591 and 0.1395 ...
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Article
Numerical simulations of turbulent flows within an infinite array of randomly placed cylinders
(2018)We address the task of modelling numerically turbulent flows within random arrays of circular cylinders, relevant for several industrial and environmental applications. Numerical simulations are employed to model infinite ...
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Article
The numerical solution of laminar flow in a re-entrant tube geometry by a Chebyshev spectral element collocation method
(1992)A Chebyshev spectral element collocation method is used for the numerical solution of laminar flow in a re-entrant tube geometry. The high accuracy of the method allows the study of the merging process of the vortices in ...
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Article
Numerical study of the combined effects of inertia, slip, and compressibility in extrusion of yield stress fluids
(2014)The axisymmetric extrudate swell flow of a compressible Herschel–Bulkley fluid with wall slip is solved numerically. The Papanastasiou-regularized version of the constitutive equation is employed, together with a linear ...
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Article
On the analogy between streamlined magnetic and solid obstacles
(2009)Analogies are elaborated in the qualitative description of two systems: the magnetohydrodynamic (MHD) flow moving through a region where an external local magnetic field (magnetic obstacle) is applied and the ordinary ...
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Article
On the combined effects of slip, compressibility, and inertia on the Newtonian extrudate-swell flow problem
(2013)We solve both the planar and axisymmetric extrudate-swell flows of a compressible Newtonian liquid with Navier slip at the wall, using the finite-element method in space and a fully-implicit finite-difference scheme in ...
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Article
On the transition to turbulence of a viscoplastic fluid past a confined cylinder: A numerical study
(2015)Three-dimensional direct numerical simulations of a Bingham fluid flowing past a confined circular cylinder have been used in order to investigate viscoplastic effects in the wake-transition regime. The case of a cylinder ...
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Article
Performance of the finite volume method in solving regularised Bingham flows: Inertia effects in the lid-driven cavity flow
(2014)We extend our recent work on the creeping flow of a Bingham fluid in a lid-driven cavity, to the study of inertial effects, using a finite volume method and the Papanastasiou regularisation of the Bingham constitutive model ...
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Article
Performance of the finite volume method in solving regularised Bingham flows: Inertia effects in the lid-driven cavity flow
(2014)We extend our recent work on the creeping flow of a Bingham fluid in a lid-driven cavity, to the study of inertial effects, using a finite volume method and the Papanastasiou regularisation of the Bingham constitutive model ...
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Article
Perturbation solution of the compressible annular Poiseuille flow of a viscous fluid
(2010)The isothermal annular Poiseuille flow of a weakly compressible Newtonian liquid with constant shear and bulk viscosities is considered. A linear equation of state is assumed and a perturbation analysis in terms of the ...
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Article
Perturbation solutions of Poiseuille flows of weakly compressible Newtonian liquids
(2009)Both the planar and axisymmetric isothermal Poiseuille flows of weakly compressible Newtonian liquids with constant shear and bulk viscosities are solved up to the second-order. A linear equation of state is assumed and a ...
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Article
Representing anisotropy of two-point second-order turbulence velocity correlations using structure tensors
(2008)A locally homogeneous representation for the two-point, second-order turbulent velocity fluctuation Rij(x,r) = 〈u′i(x)u′i(x+r)〉 is formulated in terms of three linearly independent structure tensors [Kassinos et al., J. ...
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Article
A simplified structure-based model using standard turbulence scale equations: computation of rotating wall-bounded flows
(2006)Two linear eddy-viscosity models, the v2-f and k-ω models, have been combined with an algebraic structure-based algorithm for the evaluation of the Reynolds stresses. This closure was originally designed as an integral ...
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Conference Object
Solution of viscoplastic flows with the finite volume / multigrid method
(National Technical University of Athens, 2013)We investigate the performance of the finite volume method in solving viscoplastic flows. The square lid-driven cavity flow of a Bingham plastic is chosen as the test case and the constitutive equation is regularised as ...