Turbulent flow past a bubble and an ellipsoid using shadow-image and PIV techniques

A. Tokuhiro, M. Maekawa, K. Iizuka, Koichi Hishida, M. Maeda

Research output: Contribution to journalArticle

89 Citations (Scopus)

Abstract

An experimental investigation on flow around an oscillating bubble and solid ellipsoid with a flat bottom was conducted. A single air bubble (equivalent diameter D(e) = 9.12 mm) was attached to a small disk (~1 mm) at the end of a needle and suspended across a vertical square channel (100 mm) by wire wherein water flowed downward at a constant flowrate. The solid ellipsoid (D(e) ~ 9.1 mm) was suspended across the square channel in the same manner. The equivalent diameter-based Reynolds and Eotvos number range, 1950 < Re < 2250 and 11 < Eo < 11.5, placed the bubble in the 'wobbly' regime while the flow in its wake was turbulent. A constant flowrate and one bubble size was used such that flow in the wake was turbulent. Velocity measurements of the flow field around the bubble or solid were made using a one CCD camera Digital Particle Image Velocimetry (DPIV) system enhanced by Laser Induced Fluorescence (LIF). The shape of the bubble or solid was simultaneously recorded along with the velocity using a second CCD camera and an Infrared Shadow Technique (IST). In this way both the flow-field and the boundary of the bubble (solid) were measured. The velocity vector plots of flow around and in the wake of a bubble/solid, supplemented by profiles and contours of the average and root-mean-square velocities, vorticity, Reynolds stress and turbulent kinetic energy, revealed differences in the wake flow structure behind a bubble and solid. One of the significant differences was in the inherent, oscillatory motion of the bubble which not only produced vorticity in the near-wake, but as a result of apparent vorticity stretching distributed the turbulent kinetic energy associated with this flow more uniformly on its wake, in contrast to the solid.

Original languageEnglish
Pages (from-to)1383-1406
Number of pages24
JournalInternational Journal of Multiphase Flow
Volume24
Issue number8
DOIs
Publication statusPublished - 1998 Dec

Fingerprint

particle image velocimetry
ellipsoids
turbulent flow
Turbulent flow
bubbles
Vorticity
wakes
vorticity
turbulent wakes
CCD cameras
Kinetic energy
Velocity measurement
Flow fields
flow distribution
kinetic energy
near wakes
Flow structure
Needles
Stretching
Reynolds stress

Keywords

  • Bubble oscillations
  • Digital particle image velocimetry (DPIV)
  • Infrared shadow technique (IST)
  • Laser induced fluorescence (LIF)
  • Single-bubble
  • Turbulent wake flow

ASJC Scopus subject areas

  • Fluid Flow and Transfer Processes
  • Mechanical Engineering

Cite this

Turbulent flow past a bubble and an ellipsoid using shadow-image and PIV techniques. / Tokuhiro, A.; Maekawa, M.; Iizuka, K.; Hishida, Koichi; Maeda, M.

In: International Journal of Multiphase Flow, Vol. 24, No. 8, 12.1998, p. 1383-1406.

Research output: Contribution to journalArticle

Tokuhiro, A. ; Maekawa, M. ; Iizuka, K. ; Hishida, Koichi ; Maeda, M. / Turbulent flow past a bubble and an ellipsoid using shadow-image and PIV techniques. In: International Journal of Multiphase Flow. 1998 ; Vol. 24, No. 8. pp. 1383-1406.
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