Numerical simulation of the flow behind a rotary oscillating circular cylinder

Baek, Seung-Jin; Sung, Hyung Jin

doi:10.1063/1.869610

Cited by 123 publications

(53 citation statements)

References 25 publications

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“…experimental work was followed by a series of numerical [22][23][24][25][26][27][28][29][30] and experimental investigations [31][32][33][34]. Recently, due to the maturity of control theory, optimization methods and computational fluid dynamics, optimal and suboptimal approaches attracted increased attention in flow control setting [35][36][37].…”

Section: A Generic Configuration Of Separated Flows: the Cylinder Wakmentioning

confidence: 99%

Optimal control of the cylinder wake in the laminar regime by trust-region methods and POD reduced-order models

Bergmann

Cordier

2008

Journal of Computational Physics

180

154

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In this paper, optimal control theory is used to minimize the total mean drag for a circular cylinder wake flow in the laminar regime (Re = 200). The control parameters are the amplitude and the frequency of the time-harmonic cylinder rotation. In order to reduce the size of the discretized optimality system, a Proper Orthogonal Decomposition (POD) Reduced-Order Model (ROM) is derived to be used as state equation. We then propose to employ the Trust-Region Proper Orthogonal Decomposition (TRPOD) approach, originally introduced by Fahl (2000), to update the reduced-order models during the optimization process. A lot of computational work is saved because the optimization process is now based only on low-fidelity models. A particular care was taken to derive a POD ROM for the pressure and velocity fields with an appropriate balance between model accuracy and robustness. The key enablers are the extension of the POD basis functions to the pressure data, the use of calibration methods for the POD ROM and the addition in the POD expansion of several non-equilibrium modes to describe various operating conditions. When the TRPOD algorithm is applied to the wake flow configuration, this approach converges to the minimum predicted by an open-loop control approach and leads to a relative mean drag reduction of 30% at reduced cost.

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Section: A Generic Configuration Of Separated Flows: the Cylinder Wakmentioning

confidence: 99%

Optimal control of the cylinder wake in the laminar regime by trust-region methods and POD reduced-order models

Bergmann

Cordier

2008

Journal of Computational Physics

180

154

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“…In general the detailed mechanism behind this shedding process and the subsequent drag reduction is unknown. Other studies using rotational forcing, including Okajima, Takata & Asanuma (1975), Wu, Mo & Vakili (1989), Ou (1991), Filler, Marston & Mih (1991), El-Refaee (1995), Zakharenkov (1996), Chou (1997), and Baek & Sung (1998), consider different issues at lower Reynolds numbers and for less vigorous rotations. Taneda (1978) presents curious flow visualizations suggesting that complete suppression of separation for much lower Reynolds numbers can be achieved with a large-amplitude rotational forcing, although there has been no subsequent validation of these results.…”

Section: Introductionmentioning

confidence: 99%

Investigation of a drag reduction on a circular cylinder in rotary oscillation

Shiels

Leonard

2001

J. Fluid Mech.

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Drag reduction in two-dimensional flow over a circular cylinder, achieved using rotary oscillation, was investigated with computational simulations. In the experiments of Tokumaru & Dimotakis (1991), this mechanism was observed to yield up to 80% drag reduction at Re = 15 000 for certain ranges of frequency and amplitude of sinusoidal rotary oscillation. Simulations with a high-resolution viscous vortex method were carried out over a range of Reynolds numbers (150-15 000) to explore the effects of oscillatory rotational forcing. Significant drag reduction was observed for a rotational forcing which had been very effective in the experiments. The impact of the forcing is strongly Reynolds number dependent. The cylinder oscillation appears to trigger a distinctive shedding pattern which is related to the Reynolds number dependence of the drag reduction. It appears that the source of this unusual shedding pattern and associated drag reduction is vortex dynamics in the boundary layer initiated by the oscillatory cylinder rotation. The practical efficiency of the drag reduction procedure is also discussed.

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“…To our knowledge, from a survey of existing literature, only three purely numerical studies have been made on this problem: Lu & Sato (1996), Chou (1997) and Baek & Sung (1998). Finite-difference simulations were carried out using primitive variables except for the work of Chou.…”

Section: Introductionmentioning

confidence: 99%

The flow induced by a rotationally oscillating and translating circular cylinder

2000

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The temporal development of two-dimensional viscous incompressible flow induced by an impulsively started circular cylinder which performs time-dependent rotational oscillations about its axis and translates at right angles to this axis is investigated. The investigation is based on the solutions of the unsteady Navier-Stokes equations. A series expansion for small times is developed. The Navier-Stokes equations are also integrated by a spectral-finite difference method for moderate values of time for both moderate and high Reynolds numbers. The numerical method is checked with the results of the analytical solution. The effects of the Reynolds number and of the forcing Strouhal number S on the laminar asymmetric flow structure in the near-wake region are studied. The lift and drag coefficients are also extracted from numerical results. An interesting phenomenon has been observed both in the flow patterns and in the behaviour of drag coefficients for S = π/2 at Reynolds number R = 500 and is discussed. For comparison purposes the start-up flow is determined numerically at a low Reynolds number and is found to be in good agreement with previous experimental predictions.

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Numerical simulation of the flow behind a rotary oscillating circular cylinder

Cited by 123 publications

References 25 publications

Optimal control of the cylinder wake in the laminar regime by trust-region methods and POD reduced-order models

Optimal control of the cylinder wake in the laminar regime by trust-region methods and POD reduced-order models

Investigation of a drag reduction on a circular cylinder in rotary oscillation

The flow induced by a rotationally oscillating and translating circular cylinder

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