Active control of circular cylinder flow with windward suction and leeward blowing

Gao, Donglai; Chen, Guan-Bin; Huang, Yewei; Li, Hui

doi:10.1007/s00348-018-2676-z

Cited by 62 publications

(14 citation statements)

References 21 publications

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“…Dong et al (2008) introduced a control concept characterized by combined windward suction and leeward blowing (WSLB). This concept is investigated experimentally by Gao et al (2018), and the test results show that the periodic vortex shedding in the cylinder wake is attenuated due to the action of WSLB control.…”

Section: Introductionmentioning

confidence: 99%

Effects of steady wake-jets on subcritical cylinder flow

Gao

Chen

et al. 2019

Experimental Thermal and Fluid Science

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We investigate the effects of active wake-jets (characterized by a dimensionless jet momentum coefficient C µ) on the suppression of aerodynamic forces and the manipulation of wake flow topology behind a cylindrical model through wind tunnel tests. The active jets are positioned at the rear stagnation points of the cylindrical test model. The experimental campaign is conducted at a subcritical Reynolds number of Re= 3.33 × 10 4. The surface pressure distributions around the bare and controlled cylinders are obtained by using a pressure measurement system. Apart from pressure measurements, we also obtain the streamwise and spanwise flow structures around the circular cylinder with different C µ (including C µ = 0) by employing the particle image velocimetry (PIV) technique. Pressure measurement results demonstrate that the lift force acting on the cylindrical test model is greatly reduced and drag decreased with the implementation of active wake-jets. Besides, it is found that a higher C µ contributes to a better control effectiveness in unsteady lift forces but not necessarily a better drag reduction. PIV measurement results indicate that the mechanism of the active jet control scheme is to impose steady and symmetric perturbations into the unsteady and asymmetric flows in the cylinder wake. Owing to the dynamic competition of the wake-jet flow and shear layer flows, the vortex shedding pattern behind the controlled cylinder is greatly modified, vortex formation length significantly elongated and the fluctuations of aerodynamic forces conceivably suppressed.

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Section: Introductionmentioning

confidence: 99%

Effects of steady wake-jets on subcritical cylinder flow

Gao

Chen

et al. 2019

Experimental Thermal and Fluid Science

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“…许福友等人 [15] 通过施加抑流板改变了桥梁主梁的绕流场分布, 有效抑制了主梁的涡激振动. Xin等人 [16] 在大跨度桥梁主梁上沿着展向布置被 . 作为本文的基础, 本节首先提出一种主动WSLB吸/吹气控制方法, 即迎风侧主动吸气背风侧主动吹气(windward suction and leeward blowing, WSLB), 对拉索节段模型(圆柱)绕流场进行控制并研究其控制机理 [17] . 在主动控制机理研究的基础上, 提出一种被动吸/吹气套环流动控制方法, 抑制索结构的风致振动.…”

Section: 等人unclassified

“…图 1 (网络版彩图)风洞试验模型及试验布置 [17] . 图 3 (网络版彩图)不同控制工况下索节段模型气动力系数 [17] . (a) 平均阻力系数; (b) 脉动升力系数图 4 (网络版彩图)PIV系统获得的无控及WSLB控制索结构的时均流场 [17] .…”

Section: °之间(背风侧)其压力系数分布存在较宽的平稳unclassified

Vortex dynamics-based flow control of wind effects on long-span bridges

Gao¹,

Chen²,

Yang³

et al. 2021

Sci. Sin.-Tech.

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“…In active flow control, external supply of energy is required to operate actuators that disturb the flow in steady or unsteady (usually periodic) mode [15]. For example, the flow characteristics around a cylinder in cross-flow can be modified by continuous windward suction and leeward blowing on the cylinder surface [16,17], by superimposing periodic pulsations on the exterior flow [18][19][20], or several other methods, for a more comprehensive list see the work by the authors of [6]. The benefits of AFC must be outweighed against the cost of implementing control, often in terms of energy efficiency.…”

Section: Flow Control Definitions and Preliminary Remarksmentioning

confidence: 99%

“…These images are separated in time by one-half the vortex shedding cycle so that the natural vortex shedding cycle is demonstrated. Gerrard [17] defined the vortex being shed from the cylinder when it becomes strong enough to draw the other shear layer across the wake, cutting it off from further supply of Figure 5(c) shows the flow at t=T K ¼ 0:7 after plasma fires, when the secondary vortex with negative vorticity is being released into the wake (marked by an arrow in the…”

Section: Transient Perturbationsmentioning

confidence: 99%

Active Control of Bluff-Body Flows Using Plasma Actuators

Konstantinidis

2019

Actuators

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Actuators play an important role in modern active flow control technology. Dielectric barrier discharge plasma can be used to induce localized velocity perturbations in air, so as to accomplish modifications to the global flow field. This paper presents a selective review of applications from the published literature with emphasis on interactions between plasma-induced perturbations and original unsteady fields of bluff-body flows. First, dielectric barrier discharge (DBD)-plasma actuator characteristics, and the local disturbance fields these actuators induce into the exterior flow, are described. Then, instabilities found in separated flows around bluff bodies that controlled actuation should target at are briefly presented. Key parameters for effective control are introduced using the nominally two-dimensional flow around a circular cylinder as a paradigm. The effects of the actuator configuration and location, amplitude and frequency of excitation, input waveform, as well as the phase difference between individual actuators are illustrated through examples classified based on symmetry properties. In general, symmetric excitation at frequencies higher than approximately five times the uncontrolled frequency of vortex shedding acts destructively on regular vortex shedding and can be safely employed for reducing the mean drag and lift fluctuations. Antisymmetric and symmetric excitation at low frequencies of the order of the natural frequency can amplify the wake instability and increase the mean and fluctuating aerodynamic forces, respectively, due to vortex locking-on to the excitation frequency or its subharmonics. Results from several studies show that the geometry and arrangement of the electrodes is of utmost significance. Power consumption is typically very low, but the electromechanical efficiency can be optimized by input waveform modulation.

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Active control of circular cylinder flow with windward suction and leeward blowing

Cited by 62 publications

References 21 publications

Effects of steady wake-jets on subcritical cylinder flow

Effects of steady wake-jets on subcritical cylinder flow

Vortex dynamics-based flow control of wind effects on long-span bridges

Active Control of Bluff-Body Flows Using Plasma Actuators

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