scholarly journals Two-Dimensional Simulation of the Navier-Stokes Equations for Laminar and Turbulent Flow around a Heated Square Cylinder with Forced Convection

2018 ◽  
Vol 09 (03) ◽  
pp. 291-312
Author(s):  
Rômulo D. C. Santos ◽  
Sílvio M. A. Gama ◽  
Ramiro G. R. Camacho
Keyword(s):  
Turbulent Flow ◽  
Forced Convection ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Square Cylinder ◽  
Navier Stokes Equations ◽  
Laminar And Turbulent Flow ◽  
Dimensional Simulation

scholarly journals Machine-aided turbulence theory

2018 ◽  
Vol 854 ◽  
Author(s):  
Javier Jiménez
Keyword(s):  
Turbulent Flow ◽  
Turbulent Flows ◽  
Stokes Equations ◽  
A Priori ◽  
Turbulence Theory ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Navier Stokes Equations ◽  
Future Evolution ◽  
Decaying Turbulence

The question of whether significant subvolumes of a turbulent flow can be identified by automatic means, independently of a priori assumptions, is addressed using the example of two-dimensional decaying turbulence. Significance is defined as influence on the future evolution of the flow, and the problem is cast as an unsupervised machine ‘game’ in which the rules are the Navier–Stokes equations. It is shown that significance is an intermittent quantity in this particular flow, and that, in accordance with previous intuition, its most significant features are vortices, while the least significant ones are dominated by strain. Subject to cost considerations, the method should be applicable to more general turbulent flows.

Numerical Turbulent Analysis for Flow Around a Square Cylinder Using the Finite Element Method

2003 ◽  
Author(s):  
Shinichiro Miura ◽  
Kazuhiko Kakuda
Keyword(s):  
Finite Element ◽  
Flow Field ◽  
Turbulent Flow ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Square Cylinder ◽  
Weak Formulation ◽  
Finite Element Scheme ◽  
Navier Stokes Equations ◽  
Element Scheme

A finite element scheme based on the Petrov-Galerkin weak formulation using exponential weighting functions for solving accurately, and in a stable manner, the flow field of an incompressible viscous fluid has been proposed in our previous works. In this paper, we present the Petrov-Galerkin finite element scheme for turbulent flow field. The incompressible Navier-Stokes equations are numerically integrated in time by using a fractional step strategy with second-order accurate Adams-Bashforth explicit differencing for both convection and diffusion terms. Numerical results obtained herein are compared through turbulent flow around a square cylinder at Re = 22,000 with the experimental data and other existing numerical ones.

scholarly journals Turbulent flow on a planar moving belt and a rotating disk: modelling and comparisons

2007 ◽  
Vol 587 ◽  
pp. 255-270 ◽  
Author(s):  
JOHN M. McDARBY ◽  
FRANK T. SMITH
Keyword(s):  
Turbulent Flow ◽  
Stokes Equations ◽  
Rotating Disk ◽  
Reynolds Numbers ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Navier Stokes Equations ◽  
Eddy Viscosity Model ◽  
High Reynolds ◽  
Carry Over

Modelling of the fully turbulent flow produced on a moving belt and of that induced ona rotating disk is described, for each of which a more analytical approach is adopted than previously seen. The analysis for the two-dimensional moving belt indicates novel structures and these are found to carry over directly to the rotating disk flow which, ignoring the transitional regime, is three-componential but two-dimensional due to axisymmetry. This is based on addressing the Reynolds-averaged Navier–Stokes equations together with an eddy viscosity model, with the flow structure being analysed for high Reynolds numbers. A classical (von Kármán) constant within the model plays an important and surprising role, indicating that each of the belt and the disk flows has quite a massive thickness. Comparisons made with previous work show varying degrees of agreement. The approach, including the new prediction of massive thicknesses independent of the Reynoldsnumber, is expected to extend to flows induced by rotary blades, by related rotary devices and by other configurations of industrial interest.

Direct simulation of transition in an oscillatory boundary layer

1998 ◽  
Vol 371 ◽  
pp. 207-232 ◽  
Author(s):  
G. VITTORI ◽  
R. VERZICCO
Keyword(s):  
Boundary Layer ◽  
Pressure Gradient ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Turbulent Regime ◽  
Two Dimensional ◽  
Temporal Development ◽  
Direct Simulation ◽  
Navier Stokes Equations ◽  
Oscillatory Boundary Layer

Numerical simulations of Navier–Stokes equations are performed to study the flow originated by an oscillating pressure gradient close to a wall characterized by small imperfections. The scenario of transition from the laminar to the turbulent regime is investigated and the results are interpreted in the light of existing analytical theories. The ‘disturbed-laminar’ and the ‘intermittently turbulent’ regimes detected experimentally are reproduced by the present simulations. Moreover it is found that imperfections of the wall are of fundamental importance in causing the growth of two-dimensional disturbances which in turn trigger turbulence in the Stokes boundary layer. Finally, in the intermittently turbulent regime, a description is given of the temporal development of turbulence characteristics.

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