The effect of arrangement of two circular cylinders on the maximum efficiency of Vortex-Induced Vibration power using a Scale-Adaptive Simulation model

Derakhshandeh, Javad Farrokhi; Arjomandi, Maziar; Dally, Bassam B.; Cazzolato, B.

doi:10.1016/j.jfluidstructs.2014.06.005

Cited by 37 publications

(14 citation statements)

References 28 publications

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“…This behaviour might be caused by the under-developed vortices that are shed from the wire at this elevation. Coherent vortices have been observed behind circular cylinders at an approximate distance of 3d at a Reynolds number of 10 3 , based on the cylinder diameter (d) [59]. Therefore, the underdeveloped vortices, in this case, simply perturb the boundary layer flow in the immediate vicinity of the airfoil during the pitch-up and lead to an earlier separation.…”

Section: Elevated Wirementioning

confidence: 99%

Methods to control dynamic stall for wind turbine applications

2016

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a b s t r a c tDynamic stall (DS) on a wind turbine is encountered when the sectional angles of attack of the blade rapidly exceeds the steady-state stall angle of attack due to in-flow turbulence, gusts and yawmisalignment. The process is considered as a primary source of unsteady loads on wind turbine blades and negatively influences the performance and fatigue life of a turbine. In the present article, the control requirements for DS have been outlined for wind turbines based on an in-depth analysis of the process. Three passive control methodologies have been investigated for dynamic stall control: (1) streamwise vortices generated using vortex generators (VGs), (2) spanwise vortices generated using a novel concept of an elevated wire (EW), and (3) a cavity to act as a reservoir for the reverse flow accumulation. The methods were observed to delay the onset of DS by several degrees as well as reduce the increased lift and drag forces that are associated with the DSV. However, only the VG and the EW were observed to improve the post-stall characteristics of the airfoil.

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Section: Elevated Wirementioning

confidence: 99%

Methods to control dynamic stall for wind turbine applications

2016

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“…The mesh created was approximately 45,000 elements. Farrokhi Derakhshandeh et al [9] previously showed that this number of mesh elements is sufficient to accurately capture the flow pattern around two cylinders in a turbulent flow. Considering the minimum mesh size and free stream velocity, the selected time step was set at 0.05s to achieve a converging solution.…”

Section: B Problem Definitionmentioning

confidence: 99%

“…Farrokhi Derakhshandeh J. [9] investigated the effect of arrangements of two staggered circular cylinders on the efficiency of the VIV power at high Reynolds number. They modelled 35 arrangements of the identical cylinders based on longitudinal (x/D) and lateral (y/D) distances between cylinders.…”

Section: Introductionmentioning

confidence: 99%

Effect of a rigid wall on the vortex induced vibration of two staggered circular cylinders

Derakhshandeh

Arjomandi

Cazzolato

et al. 2014

Journal of Renewable and Sustainable Energy

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Vortex Induced Vibrations (VIV) plays a key role in a wide range of engineering applications including the extraction of renewable energy. In this paper, numerical studies of the phenomenon of VIV were conducted to investigate the flow behaviour around two identical circular cylinders. The upstream cylinder was located in the vicinity of a rigid wall and downstream one was mounted on an elastic support with one degree of freedom (1-DOF). The Reynolds number based on the cylinder's diameter was kept constant at 8,700, while the separation between the upstream cylinder and the wall was varied. The results show that this separation distance known as the gap ratio has a significant effect on the dynamic behaviour of the upstream and downstream cylinders. Accordingly, the interaction of shear layers between the upstream cylinder and the rigid wall has a strong influence on the vortex dynamics of both cylinders, in particular when the upstream cylinder was mounted close to the wall. In this arrangement, a jet flow produced in the wake of the upstream cylinder significantly affects the vortex shedding frequency, and the lift and drag coefficients of both cylinders. This can alter the dynamic response of the downstream cylinder and theoretical efficiency of the VIV power.

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“…Derakhshandeh et al 6 analyzed the effect of arrangement of two circular cylinders on the maximum efficiency of VIV power using the Scale-Adaptive Simulation model, in which the upstream cylinder was fixed while the downstream was mounted elastically with one degree of freedom, and observed that cylinders offset from one another showed a higher efficiency compared to cylinders with their centres aligned. Chen et al 7 studied the cross-flow VIV characteristics of two elastically supported side-by-side circular cylinders with a center-to-center spacing ratio T/D ranging from 2 to 5 in numerical simulation.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation on coupled cross-flow and in-line vortex-induced vibration responses of two staggered circular cylinders

Zhang

Kang

Xiong

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part M:

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In order to better understand the vortex-induced vibration mechanism of multiple cylinders, this article takes a relatively simple case of two staggered circular cylinders as the embarkation point and investigates their vortex-induced vibration characteristics by model test. The experimental Reynolds number ranges from 22,000 to 88,000. The in-line gap L is set as 3.0 D, 3.6 D, 4.2 D and 5.5 D in turn, and the cross-flow gap T is set as 0.7 D, 1.1 D, 1.5 D, 1.9 D, 2.3 D and 2.7 D, respectively. By measuring the vibrating response in model test, the response differences between the two staggered cylinders and the isolated cylinder and the effects of the gaps are discussed. The results indicate that the variation trend of response of the upstream cylinder with reduced velocity is basically similar to that of the isolated cylinder. However, the downstream cylinder shows some great differences. When the in-line gap ratio L/ D is 3.6, the cross-flow amplitude curve of downstream cylinder changes from “single peak” to “double peaks” with the increase in cross-flow gap ratio T/ D, and in-line amplitude curve even shows four different kinds of forms. When L/ D is increasing, maximum amplitudes of the downstream cylinder in two directions also show an increasing trend, and the wake galloping phenomenon even appears in some conditions. Generally, the case of staggered cylinders is a generalized combination of two circular cylinders in tandem and side-by-side arrangements, and this article has extended the research scope of the double-cylinder vortex-induced vibration to arbitrary flow direction.

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The effect of arrangement of two circular cylinders on the maximum efficiency of Vortex-Induced Vibration power using a Scale-Adaptive Simulation model

Cited by 37 publications

References 28 publications

Methods to control dynamic stall for wind turbine applications

Methods to control dynamic stall for wind turbine applications

Effect of a rigid wall on the vortex induced vibration of two staggered circular cylinders

Experimental investigation on coupled cross-flow and in-line vortex-induced vibration responses of two staggered circular cylinders

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