Partially Averaged Navier-Stokes Method: Modeling and Simulation of Low Reynolds Number Effects in Flow Past a Circular Cylinder

2011 ◽  
Author(s):  
Dasia Reyes ◽  
Sunil Lakshmipathy ◽  
Sharath Girimaji
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Modeling And Simulation ◽  
Low Reynolds Number ◽  
Navier Stokes ◽  
Flow Past ◽  
Reynolds Number Effects ◽  
Low Reynolds

Steady approach of unsteady low-Reynolds-number flow past two rotating circular cylinders

2013 ◽  
Vol 736 ◽  
pp. 414-443 ◽  
Author(s):  
Y. Ueda ◽  
T. Kida ◽  
M. Iguchi
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Stokes Equations ◽  
Low Reynolds Number ◽  
Vortex Method ◽  
The Self ◽  
Circular Cylinders ◽  
Far Field ◽  
Flow Past ◽  
Low Reynolds

AbstractThe long-time viscous flow about two identical rotating circular cylinders in a side-by-side arrangement is investigated using an adaptive numerical scheme based on the vortex method. The Stokes solution of the steady flow about the two-cylinder cluster produces a uniform stream in the far field, which is the so-called Jeffery’s paradox. The present work first addresses the validation of the vortex method for a low-Reynolds-number computation. The unsteady flow past an abruptly started purely rotating circular cylinder is therefore computed and compared with an exact solution to the Navier–Stokes equations. The steady state is then found to be obtained for $t\gg 1$ with ${\mathit{Re}}_{\omega } {r}^{2} \ll t$, where the characteristic length and velocity are respectively normalized with the radius ${a}_{1} $ of the circular cylinder and the circumferential velocity ${\Omega }_{1} {a}_{1} $. Then, the influence of the Reynolds number ${\mathit{Re}}_{\omega } = { a}_{1}^{2} {\Omega }_{1} / \nu $ about the two-cylinder cluster is investigated in the range $0. 125\leqslant {\mathit{Re}}_{\omega } \leqslant 40$. The convection influence forms a pair of circulations (called self-induced closed streamlines) ahead of the cylinders to alter the symmetry of the streamline whereas the low-Reynolds-number computation (${\mathit{Re}}_{\omega } = 0. 125$) reaches the steady regime in a proper inner domain. The self-induced closed streamline is formed at far field due to the boundary condition being zero at infinity. When the two-cylinder cluster is immersed in a uniform flow, which is equivalent to Jeffery’s solution, the streamline behaves like excellent Jeffery’s flow at ${\mathit{Re}}_{\omega } = 1. 25$ (although the drag force is almost zero). On the other hand, the influence of the gap spacing between the cylinders is also investigated and it is shown that there are two kinds of flow regimes including Jeffery’s flow. At a proper distance from the cylinders, the self-induced far-field velocity, which is almost equivalent to Jeffery’s solution, is successfully observed in a two-cylinder arrangement.

Laminar Flow Past a Circular Cylinder: Reduction of Drag and Fluctuating Lift Using Upstream and Downstream Rods

2014 ◽  
Vol 493 ◽  
pp. 9-14
Author(s):  
Dedy Zulhidayat Noor ◽  
Eddy Widiyono ◽  
Suhariyanto ◽  
Lisa Rusdiyana ◽  
Joko Sarsetiyanto
Keyword(s):  
Reynolds Number ◽  
Laminar Flow ◽  
Circular Cylinder ◽  
Drag Reduction ◽  
Passive Control ◽  
Low Reynolds Number ◽  
Tandem Arrangement ◽  
Single Cylinder ◽  
Flow Past ◽  
Low Reynolds

Laminar flow past a circular cylinder has been studied numerically at low Reynolds number. The upstream and downstream rods have been used as passive control in order to reduce hydrodynamics forces acting on the cylinder. Both the upstream and downstream rods significantly contribute in reduction of drag and fluctuating lift compared to single cylinder without the rods. More detail, the upstream installation rod is more dominant in drag reduction than the downstream one. On the contrary, the downstream rod has suppressed the magnitude of the fluctuating lift almost twice that of the upstream configuration. Placing the two rods together as the upstream and downstream passive control in tandem arrangement has given more hydrodynamics forces reduction than the single rod configurations.Keywords:circular cylinder, passive control, tandem, drag, lift.

Numerical and Experimental Investigation of Low Reynolds Number Effects on Laminar Flow Separation and Transition in a Cascade of Compressor Blades

2000 ◽  
Author(s):  
Shunji Enomoto ◽  
C. Hah ◽  
G. V. Hobson
Keyword(s):  
Reynolds Number ◽  
Laminar Flow ◽  
Flow Separation ◽  
Low Reynolds Number ◽  
Numerical Procedure ◽  
Compressor Blade ◽  
Navier Stokes ◽  
Flow Transition ◽  
Reynolds Number Effects ◽  
Low Reynolds

The results of an experimental and numerical comparison of the effects of low Reynolds number on flow separation and transition in a controlled-diffusion compressor cascade are presented. The flow separation and subsequent flow transition are associated with low Reynolds number effects in the compressor blade rows. Current steady-state Reynolds-averaged Navier-Stokes codes with available turbulence and transition models do not calculate the current flow phenomena properly. An unsteady three-dimensional Navier-Stokes calculation that applies a third-order accurate upwind method has been performed and the numerical results are compared to the measurements in detail. The results from the current numerical procedure agree very well with the measurements in terms of laminar flow separation, reattachment, and subsequent flow transition at low Reynolds numbers. The present study indicates that flow separation and flow transition inside compressor blade rows at low Reynolds number are phenomena dominated by relatively larger eddies near the wall and can be simulated with the current type of unsteady numerical procedure.

Sign in / Sign up

Export Citation Format

Share Document