Imperial College London
Portrait Picture

Dr. Oliver Buxton

Faculty of Engineering, Department of Aeronautics

Reader in Experimental Fluid Mechanics
 
 
 
//

Contact

 

+44 (0)20 7594 5118o.buxton Website CV

 
 
//

Location

 

213City and Guilds BuildingSouth Kensington Campus

//

Summary

 

Publications

Citation

BibTex format

@article{Cicolin:2023:10.1016/j.jfluidstructs.2023.103918,
author = {Cicolin, M and Bearman, P and Assi, G and Buxton, O},
doi = {10.1016/j.jfluidstructs.2023.103918},
journal = {Journal of Fluids and Structures},
pages = {1--14},
title = {Bistability in the wake of a circular cylinder with passive control using two leeward rods},
url = {http://dx.doi.org/10.1016/j.jfluidstructs.2023.103918},
volume = {120},
year = {2023}
}
Download

RIS format (EndNote, RefMan)

TY  - JOUR
AB  - This paper presents an experimental investigation on the flow around a circular cylindercontrolled by a pair of rods placed close to the separated shear layers from the leewardface of the cylinder. Past research of Cicolin et al. (2021) has shown that one control rod,placed at specific positions, induces a late flow separation on the main cylinder’s surfacein a typical occurrence of the Coand effect. As a result the control rod reduced the meandrag acting on the cylinder but also produced a net mean lift force. We now presentan extension of the aforementioned study to consideration of a pair of symmetricallyarranged control rods, aimed at eliminating the mean lift force whilst maintaining a dragreduction. The experiments were carried out at a Reynolds number Re = 20, 000 basedon the diameter of the main cylinder D, with the diameter of the control rods being tentimes smaller than that of the cylinder. The centre-to-centre distances between eachcontrol rod and the cylinder was 0.7D, and the angular position of the rods varied fromθ = 120to 125, where θ is measured from the front stagnation point. Time-resolvedPIV velocity fields and hydrodynamic forces were measured for the different setups.Results show that the mean flow is asymmetric in spite of the symmetry of the geometricmodel and position of the rods. The pair of control rods induces a bistable flow, inducedby the imbalance of two colliding jets in the near wake. The dynamics were found tobe random, with the average switching time between stable states depending on theposition of the rods. The mean drag force was reduced by up to 15%, and the mean liftforce was reduced by 80% compared to the cases with a single control rod. It was alsoobserved that the control rod can induce two different types of flow separation fromthe main cylinder, one in which the flow separates from the main cylinder only onceand one in which a small separation bubble forms in proximity to the control rod beforereatta
AU  - Cicolin,M
AU  - Bearman,P
AU  - Assi,G
AU  - Buxton,O
DO  - 10.1016/j.jfluidstructs.2023.103918
EP  - 14
PY  - 2023///
SN  - 0889-9746
SP  - 1
TI  - Bistability in the wake of a circular cylinder with passive control using two leeward rods
T2  - Journal of Fluids and Structures
UR  - http://dx.doi.org/10.1016/j.jfluidstructs.2023.103918
UR  - https://www.sciencedirect.com/science/article/pii/S0889974623000865
UR  - http://hdl.handle.net/10044/1/104742
VL  - 120
ER  -
Download