Imperial College London

Professor Peter Bearman

Faculty of EngineeringDepartment of Aeronautics

Senior Research Investigator
 
 
 
//

Contact

 

+44 (0)20 7594 5055p.bearman Website

 
 
//

Location

 

317ACity and Guilds BuildingSouth Kensington Campus

//

Summary

 

Publications

Publication Type
Year
to

114 results found

Clapperton B, Bearman PW, 2018, Control of circular cylinder flow using distributed passive jets, Journal of Fluid Mechanics, Vol: 848, Pages: 1157-1178, ISSN: 0022-1120

A wind tunnel study has been carried out to investigate flow control around a hollowcircular cylinder using passive jets driven by naturally occurring pressure differences.Flow enters the cylinder through spanwise holes along the stagnation line and exitsthrough a spanwise distribution of holes at±65°. The diameter of the entry and exitholes were 1% and 0.5% of the cylinder diameter, respectively. Reynolds numbers wereat the upper end of the sub-critical regime and ranged from 3×104to 2.8×105. Jetspacings of 10% and 20% of the cylinder diameter were investigated and the ratio of theaverage jet exit velocity to the cross-flow velocity at the boundary layer edge was found torise to about 0.35 and 0.4, respectively, above a Reynolds number of 1.5×105. Findingsbased on using the surface oil flow technique revealed a repeating, organised cellularpattern downstream of adjacent jet exit holes consisting of a primary counter-rotatingvortex pair structure, followed by a secondary weaker pair. Downstream of adjacent exitholes, and centred midway between them, there exists a separation bubble which delaysfinal flow separation compared with the flow directly downstream of a jet. The variationin the angular position of boundary layer separation across the span had the effect ofsuppressing von K ́arm ́an vortex shedding. This resulted in a drag coefficient, at the upperend of the Reynolds number range studied, 14.5% lower than that found using trip wiresto initiate boundary layer transition.

Journal article

Assi G, Bearman PW, 2018, Vortex-induced vibration of a wavy elliptic cylinder, Journal of Fluids and Structures, Vol: 80, Pages: 1-21, ISSN: 0889-9746

This paper shows that three-dimensional separation lines on a wavy cylinder may be correlated by the lateral movement of the body responding to flow-induced excitations. Vortex-induced vibration (VIV) of a wavy elliptic cylinder is investigated by mean of experiments in a water channel in the range of Reynold number between 1,500 to 15,000. Results are compared with those for a plain circular cylinder of equivalent diameter with a combined mass–damping parameter of 0.018. Curves of displacement and frequency of vibration showed that the hydroelastic mechanism that drives the wavy cylinder into VIV is not different from that of a plain cylinder. Detailed decomposition of the fluid forces supports this conclusion. The reason for such similar behaviour is the correlation of the sinuous separation lines as the wavy cylinder starts to oscillate. Flow visualization reveals that the three-dimensional surface of the wavy cylinder affects the formation of vortices in the near wake, generating streamwise and cross-flow vorticity associated with the wavelength of the surface. However, once the cylinder is free to respond to VIV, moving in the cross-flow direction, coherent vortex filaments once more dominate the near wake.

Journal article

Bearman PW, Gustavo A, Vortex-induced vibration of a wavy elliptic cylinder, Journal of Fluids and Structures, ISSN: 0889-9746

Journal article

Assi GRS, Bearman PW, 2015, Transverse galloping of circular cylinders fitted with solid and slotted splitter plates, JOURNAL OF FLUIDS AND STRUCTURES, Vol: 54, Pages: 263-280, ISSN: 0889-9746

Journal article

Assi GRS, Bearman PW, Tognarelli MA, 2014, On the stability of a free-to-rotate short-tail fairing and a splitter plate as suppressors of vortex-induced vibration, OCEAN ENGINEERING, Vol: 92, Pages: 234-244, ISSN: 0029-8018

Journal article

Assi GRS, Bearman PW, Carmo BS, Meneghini JR, Sherwin SJ, Willden RHJet al., 2013, The role of wake stiffness on the wake-induced vibration of the downstream cylinder of a tandem pair, JOURNAL OF FLUID MECHANICS, Vol: 718, Pages: 210-245, ISSN: 0022-1120

When a pair of tandem cylinders is immersed in a flow the downstream cylinder can be excited into wake-induced vibrations (WIV) due to the interaction with vortices coming from the upstream cylinder. Assi, Bearman & Meneghini (J. Fluid Mech., vol. 661, 2010, pp. 365–401) concluded that the WIV excitation mechanism has its origin in the unsteady vortex–structure interaction encountered by the cylinder as it oscillates across the wake. In the present paper we investigate how the cylinder responds to that excitation, characterising the amplitude and frequency of response and its dependency on other parameters of the system. We introduce the concept of wake stiffness, a fluid dynamic effect that can be associated, to a first approximation, with a linear spring with stiffness proportional to Re and to the steady lift force occurring for staggered cylinders. By a series of experiments with a cylinder mounted on a base without springs we verify that such wake stiffness is not only strong enough to sustain oscillatory motion, but can also dominate over the structural stiffness of the system. We conclude that while unsteady vortex–structure interactions provide the energy input to sustain the vibrations, it is the wake stiffness phenomenon that defines the character of the WIV response.

Journal article

Bearman PW, 2011, Circular cylinder wakes and vortex-induced vibrations, International Union of Theoretical and Applied Mechanics (IUTAM) Symposium on Bluff Body Wakes and Vortex-Induced Vibrations, Publisher: ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, Pages: 648-658, ISSN: 0889-9746

Conference paper

Carmo BS, Sherwin SJ, Bearman PW, Willden RHJet al., 2011, Flow-induced vibration of a circular cylinder subjected to wake interference at low Reynolds number, JOURNAL OF FLUIDS AND STRUCTURES, Vol: 27, Pages: 503-522, ISSN: 0889-9746

Journal article

Huera-Huarte FJ, Bearman PW, 2011, Vortex and wake-induced vibrations of a tandem arrangement of two flexible circular cylinders with near wake interference, JOURNAL OF FLUIDS AND STRUCTURES, Vol: 27, Pages: 193-211, ISSN: 0889-9746

Journal article

Assi GRS, Bearman PW, Tognarelli MA, Rodrigues JRHet al., 2011, THE EFFECT OF ROTATIONAL FRICTION ON THE STABILITY OF SHORT-TAILED FAIRINGS SUPPRESSING VORTEX-INDUCED VIBRATIONS, 30th International Conference on Ocean, Offshore and Arctic Engineering, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 389-+

Conference paper

Assi GRS, Bearman PW, Meneghini JR, 2010, On the wake-induced vibration of tandem circular cylinders: the vortex interaction excitation mechanism, JOURNAL OF FLUID MECHANICS, Vol: 661, Pages: 365-401, ISSN: 0022-1120

Journal article

Assi GRS, Bearman PW, Kitney N, Tognarelli MAet al., 2010, Suppression of wake-induced vibration of tandem cylinders with free-to-rotate control plates, JOURNAL OF FLUIDS AND STRUCTURES, Vol: 26, Pages: 1045-1057, ISSN: 0889-9746

Journal article

Huera-Huarte FJ, Bearman PW, 2010, DPIV in the wake of a tandem arrangement of two flexible circular cylinders, JOURNAL OF VISUALIZATION, Vol: 13, Pages: 195-202, ISSN: 1343-8875

Journal article

Assi GRS, Bearman PW, Meneghini JR, 2010, WAKE-INDUCED VIBRATION OF A PAIR OF CIRCULAR CYLINDERS AND ITS DEPENDENCY ON REYNOLDS NUMBER, 7th Int Symposium on Fluid-Structure Interactions, Flow-Sound Interactions, and Flow-Induced Vibration and Noise/Summer Meeting of the Fluids Engineering Division of ASME, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 233-240

Conference paper

Bearman PW, 2009, Understanding and predicting vortex-induced vibrations, JOURNAL OF FLUID MECHANICS, Vol: 634, Pages: 1-4, ISSN: 0022-1120

Journal article

Huera-Huarte FJ, Bearman PW, 2009, Wake structures and vortex-induced vibrations of along flexible cylinder-Part 2: Drag coefficients and vortex modes, JOURNAL OF FLUIDS AND STRUCTURES, Vol: 25, Pages: 991-1006, ISSN: 0889-9746

Journal article

Huera-Huarte FJ, Bearman PW, 2009, Wake structures and vortex-induced vibrations of along flexible cylinder-Part 1: Dynamic response, JOURNAL OF FLUIDS AND STRUCTURES, Vol: 25, Pages: 969-990, ISSN: 0889-9746

Journal article

Assi GRS, Bearman PW, Kitney N, 2009, Low drag solutions for suppressing vortex-induced vibration of circular cylinders, 5th Conference on Bluff Body Wakes and Vortex-Induced Vibrations (BBVIV-5), Publisher: ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, Pages: 666-675, ISSN: 0889-9746

Conference paper

Assi GRS, Bearman PW, 2009, VIV AND WIV SUPPRESSION WITH PARALLEL CONTROL PLATES ON A PAIR OF CIRCULAR CYLINDERS IN TANDEM, 28th International Conference on Ocean, Offshore and Arctic Engineering, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 263-268

Conference paper

Assi GRS, Bearman PW, 2008, VIV SUPPRESSION AND DRAG REDUCTION WITH PIVOTED CONTROL PLATES ON A CIRCULAR CYLINDER, 27th International Conference on Offshore Mechanics and Arctic Engineering, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 871-874

Conference paper

Assi GRS, Bearman PW, Meneghini JR, 2008, UNSTEADY RESPONSE OF A CIRCULAR CYLINDER UNDER WAKE-INDUCED EXCITATION FROM A FIXED UPSTREAM CYLINDER, 9th International Conference on Flow-Induced Vibration, Publisher: ACAD SCI CZECH REPUBLIC, INST THERMOMECHANICS, Pages: 279-+

Conference paper

Huera Huarte FJ, Bearman PW, 2008, WAKE STRUCTURES AND DYNAMIC RESPONSE OF ONE AND TWO LONG FLEXIBLE CYLINDERS UNDERGOING VORTEX-INDUCED VIBRATIONS, 9th International Conference on Flow-Induced Vibration, Publisher: ACAD SCI CZECH REPUBLIC, INST THERMOMECHANICS, Pages: 419-+

Conference paper

Bruno S Carmo, Spencer J Sherwin, Peter W Bearman, Richard HJ Willdenet al., 2008, Wake Transition in the flow around two circular cylinders in staggered arrangements, Journal of Fluid Mechanics, Vol: 597, Pages: 1-29

The wake transition of the flow around two circular cylinders placed in staggered arrangements with fixed streamwise separation of 5D and cross stream separation varying from 0D to 3D has been studied. The wake transition is compared to that of a single isolated cylinder. Linear stability analysis utilising Floquet theory and direct numerical simulations using a spectral/hp element spatial discretisation were carried out. The unstable modes that first appear in the wake transition of the flow around a single cylinder, which are the long spanwise wavelength mode A and the short spanwise wavelength mode B, are also found in the flow around the staggered arrangements. However, a third mode, referred to as mode C, is also present in the wake transition of the flow around staggered arrangements, depending on the relative positioning of the cylinders. This mode has an intermediate spanwise wavelength and period-doubling character. The structure and onset characteristics of mode C are analysed and the non-linear character of the bifurcation for this mode is investigated.

Journal article

Zhu G, Bearman PW, Graham JMR, 2007, Prediction of drag and lift of wings from velocity and vorticity fields, AERONAUTICAL JOURNAL, Vol: 111, Pages: 699-704, ISSN: 0001-9240

Journal article

Bearman PW, Chaplin JR, Fontaine E, Graham JMR, Herfjord K, Lima A, Meneghini JR, Schulz KW, Wiliden RHJet al., 2007, Comparison of CFD predictions of multi-mode vortex-induced vibrations of a tension riser with laboratory measurements, 6th Symposium on Fluid-Structure Interactions, Aeroelasticity and Flow-Induced Vibration and Noise, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 147-156

Conference paper

Assi GRS, Bearman PW, Meneghini JR, 2007, Unsteady force measurements on a responding circular cylinder in the wake of an upstream cylinder, 26th International Conference on Offshore Mechanics and Arctic Engineering, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 633-639

Conference paper

Bearman PW, Huera-Huarte FJ, Chaplin JR, 2007, The hydrodynamic forces acting on a long flexible circular cylinder responding to VIV, 6th Symposium on Fluid-Structure Interactions, Aeroelasticity and Flow-Induced Vibration and Noise, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 611-619

Conference paper

Assi GRS, Meneghini JR, Aranha JAP, Bearman PW, Casaprima Eet al., 2006, Experimental investigation of flow-induced vibration interference between two circular cylinders, 4th Conference on Bluff Body Wakes and Vortex-Induced Vibrations, Publisher: ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, Pages: 819-827, ISSN: 0889-9746

Conference paper

Brankovic M, Bearman PW, 2006, Measurements of transverse forces on circular cylinders undergoing vortex-induced vibration, 4th Conference on Bluff Body Wakes and Vortex-Induced Vibrations, Publisher: ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD, Pages: 829-836, ISSN: 0889-9746

Conference paper

Huera-Huarte FJ, Bearman PW, Chaplin JR, 2006, On the force distribution along the axis of a flexible circular cylinder undergoing multi-mode vortex-induced vibrations, 4th Conference on Bluff Body Wakes and Vortex-Induced Vibrations, Publisher: ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, Pages: 897-903, ISSN: 0889-9746

Conference paper

This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.

Request URL: http://wlsprd.imperial.ac.uk:80/respub/WEB-INF/jsp/search-html.jsp Request URI: /respub/WEB-INF/jsp/search-html.jsp Query String: respub-action=search.html&id=00000454&limit=30&person=true