Large Eddy Simulation of a Smooth Circular Cylinder Oscillating Normal to a Uniform Flow

2000 ◽  
Vol 122 (4) ◽  
pp. 694-702 ◽  
Author(s):  
Mustafa Tutar ◽  
Arne E. Holdo̸
Keyword(s):  
Circular Cylinder ◽  
Numerical Evaluation ◽  
Hydrodynamic Force ◽  
Uniform Flow ◽  
Transitional Flow ◽  
Finite Element Code ◽  
Law Of The Wall ◽  
Eddy Simulation ◽  
Steady Current ◽  
Large Eddy

Results of a numerical evaluation of transitional flow around a circular cylinder forced to oscillate in a direction normal to a uniform flow are presented. The cylinder is considered to be a representative of a single riser exposed to a steady current. Numerical simulations were carried out using the LES method in 2-D and 3-D with a near-wall approach that was developed without using a “law of the wall” for a finite element code (FEM). The 3-D simulations were compared with the 2-D results and experimental data in order to assess the relative performance of the 3-D LES simulations. The results show that 3-D LES gives more realistic flow field predictions and can further remove overconservatism in the prediction of hydrodynamic force coefficients. [S0098-2202(00)01103-2]

scholarly journals Large Eddy Simulation of Flow Past a Stationary and Controlled Oscillating Circular Cylinder at Re=5500

2013 ◽  
Author(s):  
Sunghan Kim ◽  
Philip A. Wilson ◽  
Zhi-Min Chen
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Large Eddy Simulation ◽  
Accurate Method ◽  
Excitation Amplitude ◽  
Uniform Flow ◽  
Cylinder Wake ◽  
Oscillating Cylinder ◽  
Eddy Simulation ◽  
Large Eddy

Vortex shedding from a stationary cylinder and transversely oscillating circular cylinder in a uniform flow at a Reynolds number of 5500 is numerically studied by three-dimensional Large Eddy Simulation (LES). The filtered equations are discretised using the finite volume method with an O-type structured grid and a second-order accurate method in both time and space. Firstly, the main wake parameters of a stationary cylinder are examined and compared for different grid resolutions. Secondly, a transversely oscillating cylinder with a constant amplitude in a uniform flow is investigated. The cylinder oscillation frequency ranges between 0.75 and 0.95 of the natural Kármán frequency, and the excitation amplitude is 50% of the cylinder diameter. Comparisons with the available experimental data indicate that the present study has properly predicted the flow statistics of the cylinder wake for both the fixed and oscillating cylinder case, and numerically captured the vortex switching phenomenon, which is characterized by changes in forces and wake mode of shedding observed in the previous experiments at high values of Reynolds number.

Detailed Investigation of Detached-Eddy Simulation for the Flow Past a Circular Cylinder at Re=3900

2012 ◽  
Vol 232 ◽  
pp. 471-476 ◽  
Author(s):  
Rui Zhao ◽  
Chao Yan
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Flow Structures ◽  
Detached Eddy Simulation ◽  
Eddy Simulation ◽  
Flow Past ◽  
Large Eddy ◽  
Mesh Resolution ◽  
Physical Phenomena

The flow past a circular cylinder at a subcritical Reynolds number 3900 was simulated by the method of detached-eddy simulation (DES). The objective of this present work is not to investigate the physical phenomena of the flow but to study modeling as well as numerical aspects which influence the quality of DES solutions in detail. Firstly, four typical spanwise lengths are chosen and the results are systematically compared. The trend of DES results along the span increment is different from previous large-eddy simulation (LES) investigation. A wider spanwise length does not necessary improve the results. Then, the influence of mesh resolution is studied and found that both too coarse and over refined grids will deteriorate the performance of DES. Finally, different orders of numerical schemes are applied in the inviscid fluxes and the viscous terms. The discrepancies among different schemes are found tiny. However, the instantaneous flow structures produced by 5th order WENO with 4th order central differencing scheme are more abundant than the others. That is, for the time-averaged quantities, the second-order accurate schemes are effective enough, whereas the higher-order accurate methods are needed to resolve the transient characteristics of the flow.

LES Analysis of Turbulence Effects on Unsteady Flows Past a Circular Cylinder

2003 ◽  
Author(s):  
Tetsuro Tamura ◽  
Yoshiyuki Ono ◽  
Kohji Hashida
Keyword(s):  
Circular Cylinder ◽  
Shear Layer ◽  
Bluff Body ◽  
Unsteady Flows ◽  
Aerodynamic Characteristics ◽  
Cylinder Wake ◽  
Eddy Simulation ◽  
Inflow Boundary Condition ◽  
Large Eddy ◽  
Turbulence Effects

Recent advancement of LES (Large Eddy Simulation) technique for turbulent wake has made it possible to numerically investigate the turbulence effects on aerodynamic characteristics of a bluff body. Here we carry out LES of wake flows past a circular cylinder in the subcritical Reynolds number regime. For inflow boundary condition, homogeneous turbulence generated statistically is given time-sequentially. We bring into focus the interaction between the oncoming turbulence and the shear layer separated from a circular cylinder. Shear layer instability easily occurs under such a stimulation and details of its behavior are visualized. Turbulence effects on unsteady flows in the cylinder wake are discussed. The resulting aerodynamic characteristics and their physical mechanism are clarified.

Prediction of Unsteady Loading on a Circular Cylinder in High Reynolds Number Flows Using Large Eddy Simulation

2005 ◽  
Author(s):  
Sung-Eun Kim ◽  
L. Srinivasa Mohan
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Turbulent Viscosity ◽  
Reynolds Numbers ◽  
Unstructured Meshes ◽  
Navier Stokes ◽  
Step Method ◽  
Fractional Step Method ◽  
Eddy Simulation ◽  
Large Eddy

Large eddy simulations were carried out for the flow around a hydrodynamically smooth, fixed circular cylinder at two Reynolds numbers, one at a subcritical Reynolds number (Re = 1.4 × 105) and the other at a supercritical Reynolds number (Re = 1.0 × 106). The computations were made using a parallelized finite-volume Navier-Stokes solver based on a multidimensional linear reconstruction scheme that allows use of unstructured meshes. Central differencing was used for discretization of both convection and diffusion terms. Time-advancement scheme, based on an implicit, non-iterative fractional-step method, was adopted in conjunction with a three-level, backward second-order temporal discretization. Subgrid-scale turbulent viscosity was modeled by a dynamic Smagorinsky model adapted to arbitrary unstructured meshes with the aid of a test-filter applicable to arbitrary unstructured meshes. The present LES results closely reproduced the flow features observed in experiments at both Reynolds numbers. The time-averaged mean drag coefficient, root-mean-square force coefficients and the frequency content of fluctuating forces (vortex-shedding frequency) are predicted with a commendable accuracy.

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