Wall-mounted flexible plates in a two-dimensional channel trigger early flow instabilities

Singh, Gurnam; Lakkaraju, Rajaram

doi:10.1103/physreve.100.023109

Cited by 10 publications

(2 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Once U∞ > Ucr, the plate gets streaming and is prone to self-excited oscillations, similar to what happens for a streamwise-aligned standard flag (Yu et al 2019). The flapping plate results in large-scale vortices at its tip (Jin et al 2018a(Jin et al , 2018b, which has been successfully applied in the enhancement in heat exchange in a channel flow (Chen et al 2020;Joshi et al 2015;Lee et al 2017Lee et al , 2018Singh and Lakkaraju, 2019). Utilization of plate in flow control for bluff bodies dates to the study completed by Bearman (1965).…”

Section: Introductionmentioning

confidence: 95%

Control of the flow around a finite square cylinder with a flexible plate attached at the free end

et al. 2022

View full text Add to dashboard Cite

A flexible plate vertically clamped at the free-end leading edge was used to modulate the aerodynamic forces on a wall-mounted finite square cylinder. The side width (d) of the cylinder was 40 mm and the aspect ratio (H/d) was 5. The flexible plate was made of low-density Polyethylene, with a width of d and thickness of 0.04 mm. The length of the flexible plate ranged from d/8 to d.All measurements were carried out in a low-speed wind tunnel with the free-stream velocity (U∞) ranging from 4 to 20 m/s, corresponding to the Reynolds number ranging from 10960 to 54800. It was found that the flexible plate behaves distinctly depending on its length and has significant effects on the aerodynamic forces on the finite square cylinder. When U∞ is smaller than the critical velocity Ucr, which is closely related to the length of the plate, the plate statically deforms, having a negligible influence on the aerodynamic forces on the cylinder. When U∞ exceeds Ucr, the plate flaps periodically, resulting in a significant reduction in the aerodynamic forces. The maximum reduction in the mean drag, fluctuating drag and fluctuating lateral force reaches approximately 5%, 25% and 60%, respectively. The reduction in the aerodynamic forces is insensitive to both plate length and flapping frequency. Flow visualization and particle image velocimetry (PIV) results point out that the flapping plate induces large-scale vortices in the free-end shear flow, which suppress the formation of spanwise vortex shedding and make the upper part of the near wake symmetrical.The flapping configuration of the flexible plate and the corresponding pressure fluctuation on the This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Hanfeng Wang (王汉封), Chongyu Zhao (赵崇宇), Lingwei Zeng (曾令伟), Md. Mahbub Alam, and Hui Tang (唐辉), "Control of the flow around a finite square cylinder with a flexible plate attached at the free end", Physics of Fluids 34, 027109 (2022) and may be found at

show abstract

Section: Introductionmentioning

confidence: 95%

Control of the flow around a finite square cylinder with a flexible plate attached at the free end

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Chen et al (2020) extended this research by considering scenarios involving multiple wall-mounted flexible flags as VGs. In another study, Singh & Lakkaraju (2019) numerically characterized the flow behaviour when flexible plates were anchored to opposite walls of a channel. Their findings reveal that wall-mounted flexible plates induce early flow instabilities, resulting in enhanced flow mixing levels.…”

Section: Introductionmentioning

confidence: 99%

Buckled elastic sheet as a vortex generator in dual channels

Cui,

Wang,

Ren

et al. 2024

J. Fluid Mech.

View full text Add to dashboard Cite

This study presents a dual-channel vortex generator (VG) that leverages the snap-through behaviour of flexible sheets. The VG outperforms a similar-sized rigid VG in generating vortices within dual-channel flows while minimizing pressure loss. Numerical simulations using the immersed boundary-lattice Boltzmann method analyse the dynamics and vortex generation performance of the sheet under various system parameters. Two distinct modes are identified for the elastic sheet: a sustained snap-through mode (SSTM) and a dormant mode (DM). The sheet's mode is predominantly influenced by its length ratio (L*), bending stiffness $(K_b^\ast )$ and flow strength, with the mass ratio having a minimal impact. The sheet exhibiting regular SSTM can effectively generate vortices in both channels and the vortex generation performance can be conveniently tuned by altering the sheet's initial buckling (i.e. L*). An increase in $K_b^\ast $ results in a higher critical Reynolds number (Rec) required for mode transition. An increase in L*, however, initially raises Rec and then lowers it, suggesting an optimal length ratio (approximately 0.7 for our considered system) for minimizing the Rec necessary to trigger SSTM. Furthermore, a disparity in the flow strength between channels is found to suppress the snap-through of the sheet; a greater disparity, however, is permissible to induce the SSTM of more compliant sheets. These findings underscore the potential of snap-through behaviour for enhanced flow manipulation in dual-channel systems.

show abstract

Parametric study on the mixing and pressure loss of channel flow behind cylinder connected with Y-shaped elastic flag

Liao

Jing

2023

Chemical Engineering and Processing - Process Intensification

View full text Add to dashboard Cite

Wall-mounted flexible plates in a two-dimensional channel trigger early flow instabilities

Cited by 10 publications

References 56 publications

Control of the flow around a finite square cylinder with a flexible plate attached at the free end

Control of the flow around a finite square cylinder with a flexible plate attached at the free end

Buckled elastic sheet as a vortex generator in dual channels

Parametric study on the mixing and pressure loss of channel flow behind cylinder connected with Y-shaped elastic flag

Contact Info

Product

Resources

About