Pressure gradient effects on the large-scale structure of turbulent boundary layers

Zambri Harun, Jason P. Monty, Romain Mathis, Ivan Marusic

Research output: Contribution to journalArticle

84 Citations (Scopus)

Abstract

Abstract Research into high-Reynolds-number turbulent boundary layers in recent years has brought about a renewed interest in the larger-scale structures. It is now known that these structures emerge more prominently in the outer region not only due to increased Reynolds number (Metzger & Klewicki, Phys. Fluids, vol. 13(3), 2001, pp. 692-701; Hutchins & Marusic, J. Fluid Mech., vol. 579, 2007, pp. 1-28), but also when a boundary layer is exposed to an adverse pressure gradient (Bradshaw, J. Fluid Mech., vol. 29, 1967, pp. 625-645; Lee & Sung, J. Fluid Mech., vol. 639, 2009, pp. 101-131). The latter case has not received as much attention in the literature. As such, this work investigates the modification of the large-scale features of boundary layers subjected to zero, adverse and favourable pressure gradients. It is first shown that the mean velocities, turbulence intensities and turbulence production are significantly different in the outer region across the three cases. Spectral and scale decomposition analyses confirm that the large scales are more energized throughout the entire adverse pressure gradient boundary layer, especially in the outer region. Although more energetic, there is a similar spectral distribution of energy in the wake region, implying the geometrical structure of the outer layer remains universal in all cases. Comparisons are also made of the amplitude modulation of small scales by the large-scale motions for the three pressure gradient cases. The wall-normal location of the zero-crossing of small-scale amplitude modulation is found to increase with increasing pressure gradient, yet this location continues to coincide with the large-scale energetic peak wall-normal location (as has been observed in zero pressure gradient boundary layers). The amplitude modulation effect is found to increase as pressure gradient is increased from favourable to adverse.

Original languageEnglish
Pages (from-to)477-498
Number of pages22
JournalJournal of Fluid Mechanics
Volume715
DOIs
Publication statusPublished - 25 Jan 2013

Fingerprint

turbulent boundary layer
Pressure gradient
pressure gradients
Boundary layers
Amplitude modulation
boundary layers
Fluids
fluids
Reynolds number
Turbulence
turbulence
roots of equations
high Reynolds number
wakes
Decomposition
decomposition

Keywords

  • boundary layers
  • turbulent boundary layers
  • turbulent flows

ASJC Scopus subject areas

  • Mechanical Engineering
  • Mechanics of Materials
  • Condensed Matter Physics

Cite this

Pressure gradient effects on the large-scale structure of turbulent boundary layers. / Harun, Zambri; Monty, Jason P.; Mathis, Romain; Marusic, Ivan.

In: Journal of Fluid Mechanics, Vol. 715, 25.01.2013, p. 477-498.

Research output: Contribution to journalArticle

Harun, Zambri ; Monty, Jason P. ; Mathis, Romain ; Marusic, Ivan. / Pressure gradient effects on the large-scale structure of turbulent boundary layers. In: Journal of Fluid Mechanics. 2013 ; Vol. 715. pp. 477-498.
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