Control of cylinder wake flow and noise through a downstream porous treatment

Xu, Chunxiao; Mao, Yijun; Hu, Zhiwei

doi:10.1016/j.ast.2019.03.027

Cited by 40 publications

(5 citation statements)

References 47 publications

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“…As can be seen, there are good agreement for second-order statistics with both simulation result from Ma et al [28] and Lehmkuhl et al [29] and experimental results from Parnaudeau et al [30]. More studies on the numerical validation can be also found in [12].…”

Section: Numerical Validationsupporting

confidence: 73%

“…The studies mentioned above control the flow by coating porous materials on the cylinder surface, while Xu et al [12] recently developed an off-body-based flow control method, where the porous material was fixed downstream rather than coated on the cylinder surface. The numerical results show that the porous material located downstream the cylinder is another effective method for suppressing pressure fluctuations of the cylinder surface.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Study of Porous Treatments on Controlling Flow around a Circular Cylinder

2022

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Porous materials fixed on and downstream the cylinder can reach a much better effect in suppressing wall pressure fluctuations. In the present paper, numerical comparative studies have been conducted to investigate passive control of flow past a cylinder surface, in which three schemes with different porous treatments are applied to compare their pros and cons. The results show all of the three schemes of porous materials increase the time-averaged flow drag and reduce fluctuations of lift and drag forces. It can be concluded the velocity gradient reduction inside the boundary layer and the vortex shedding delay through porous coating, as well as reverse transition from turbulent vortex shedding into laminar through porous treatment downstream the cylinder, are main flow control mechanisms of porous materials. These mechanisms all reduce fluctuations of lift and drag fluctuations, but have a distinct effect on the features of wake evolution, such as the wake width and length as well as the fluctuating components of the flow velocity. In addition, the wake evolution is highly affected by the location of porous materials.

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Section: Numerical Validationsupporting

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Numerical Study of Porous Treatments on Controlling Flow around a Circular Cylinder

2022

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“…The novel framework can reduce the noise efficiently without compromising the aerodynamic performance. Xu et al [21] developed an off-body-based method to control the unsteady flow separation by fixing porous materials downstream of bluff bodies. They studied the flow past a circular cylinder at a subcritical Reynolds number.…”

Section: Introductionmentioning

confidence: 99%

A numerical study of heat transfer effects and aerodynamic noise reduction in superheated steam flow passing a temperature and pressure regulation valve

Qian

Chen

Jin

et al. 2020

Numerical Heat Transfer, Part A: Applications

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Steam is a common medium in thermal engineering. When it flows through a throttling element, the aerodynamic noise may occur due to the disturbance. In this investigation, superheated steam flowing through a Venturi tube, one of the main parts in a temperature and pressure regulation valve, at different thermal conditions is studied to analyze to effects of heat transfer on the acoustic power. With a high temperature and a low pressure, the superheated steam is treated as ideal gas. The flow velocity is high, so the k-epsilon turbulent model is used, with the compressible steam. The results show that under the adiabatic condition, the acoustic power mainly influenced by the turbulent characteristics, such as the dissipation rate and the turbulent kinetic energy. Comparing the acoustic power levels at different thermal conditions, it is found that a lower temperature results to a lower acoustic power.

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“…5 Therefore, the numerical computation of aerodynamic and aeroacoustic characteristics of bluff bodies (mainly circular cylinders) have received extensive attention. [6][7][8][9][10][11][12][13][14][15] In this paper, we shall concentrate on a passive flow control method [16][17][18][19][20][21][22][23] using wavy circular cylinders for reducing the aerodynamic drag and aeroacoustic sound.…”

Section: Introductionmentioning

confidence: 99%

Optimization of wavy cylinder for aerodynamic drag and aeroacoustic sound reduction using computational fluid dynamics analysis

Karthik

Jeyakumar

Sebastin

2020

Proceedings of the Institution of Mechanical Engineers, Part C:

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Motivated by the requirement to lessen the aerodynamic drag and aeroacoustic sound of the bluff bodies, the present paper is devoted to a numerical analysis of the aerodynamics and aeroacoustics related with the flow past wavy circular cylinders. Based on the efficient flow control method, as has been presented by preceding researchers, the existing work embarks upon an investigation on the wavy cylinder at a various wavelength and amplitude conditions. Computations are performed for a circular cylinder of the length-to-diameter ratio ( L/ D) of 25 at a Reynolds number ( Re) of 97300 using large eddy simulation and Ffowcs Williams- Hawking’s acoustic analogy. Firstly, the cylinder without waviness is subjected to a uniform incoming flow is considered for validation against measurements. Secondly, various collection of wave shape parameters, specifically dimensionless wavelength λ/ D (=1 to 2.5), and wave amplitude a/ D (=0.05 to 0.2) have been taken into consideration. It is disclosed that the proper selection of shape parameters could significantly reduce the drag and sound emission levels, compared to the normal cylinder. Finally, a multi-objective particle swarm optimization was performed using the radial basis neural network to simultaneously reduce the aerodynamic drag and sound emission, with λ/ D and a/ D as design variables. We recognized a critical λ/ D and a/ D for the wavy circular cylinder at the considered subcritical Re.

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Control of cylinder wake flow and noise through a downstream porous treatment

Cited by 40 publications

References 47 publications

Numerical Study of Porous Treatments on Controlling Flow around a Circular Cylinder

Numerical Study of Porous Treatments on Controlling Flow around a Circular Cylinder

A numerical study of heat transfer effects and aerodynamic noise reduction in superheated steam flow passing a temperature and pressure regulation valve

Optimization of wavy cylinder for aerodynamic drag and aeroacoustic sound reduction using computational fluid dynamics analysis

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