The effects of spatial resolution in turbulent boundary layers with pressure gradients

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

Single normal hot-wire measurements of the streamwise component of velocity were taken in boundary layer flows subjected to pressure gradients at matched friction Reynolds numbers Reτ ≈ 3000. To evaluate spatial resolution effects, the sensor lengths are varied in both adverse pressure gradient (APG) and favorable pressure gradient (FPG). A control boundary layer flow in zero pressure gradient ZPG is also presented. It is shown here that, when the sensor length is maintained a constant value, in a contant Reynolds number, the near-wall peak increases with (adverse) pressure gradient. Both increased contributions of the small-scale and especially large-scale features are attributed to the increased broadband turbulence intensities. The two-mode increase, one centreing in the near-wall region and the other one in the outer region, makes spatial resolution studies in boundary layer flow more complicated. The increased large-scale features in the near-wall region of an APG flow is similar to large-scales increase due to Reynolds number in ZPG flow. Additionally, there is also an increase of the small-scales in the near-wall region when the boundary layer is exposed to adverse pressure gradient (while the Reynolds number is constant). In order to collapse the near-wall peaks for APG, ZPG and FPG flows, the APG flow has to use the longest sensor and conversely, the FPG has to use the shortest sensor. This study recommends that the empirical prediction by Huthins et. al. (2009) to be reevaluated if pressure gradient flows were to be considered such that the magnitude of the near-wall peak is also a function of the adverse pressure gradient parameter.

Original languageEnglish
Title of host publicationApplied Mechanics and Materials
Pages109-117
Number of pages9
Volume225
DOIs
Publication statusPublished - 2012
EventAEROTECH IV - 2012 - Kuala Lumpur
Duration: 21 Nov 201222 Nov 2012

Publication series

NameApplied Mechanics and Materials
Volume225
ISSN (Print)16609336
ISSN (Electronic)16627482

Other

OtherAEROTECH IV - 2012
CityKuala Lumpur
Period21/11/1222/11/12

Fingerprint

Pressure gradient
Boundary layers
Boundary layer flow
Reynolds number
Sensors
Turbulence
Wire
Friction

Keywords

  • Pressure gradients
  • Spatial resolution
  • Turbulent boundary layer

ASJC Scopus subject areas

  • Engineering(all)

Cite this

Harun, Z., Isa, M. D., Mohammad Rasani, M. R., & Abdullah, S. (2012). The effects of spatial resolution in turbulent boundary layers with pressure gradients. In Applied Mechanics and Materials (Vol. 225, pp. 109-117). (Applied Mechanics and Materials; Vol. 225). https://doi.org/10.4028/www.scientific.net/AMM.225.109

The effects of spatial resolution in turbulent boundary layers with pressure gradients. / Harun, Zambri; Isa, Mohamad Dali; Mohammad Rasani, Mohammad Rasidi; Abdullah, Shahrir.

Applied Mechanics and Materials. Vol. 225 2012. p. 109-117 (Applied Mechanics and Materials; Vol. 225).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Harun, Z, Isa, MD, Mohammad Rasani, MR & Abdullah, S 2012, The effects of spatial resolution in turbulent boundary layers with pressure gradients. in Applied Mechanics and Materials. vol. 225, Applied Mechanics and Materials, vol. 225, pp. 109-117, AEROTECH IV - 2012, Kuala Lumpur, 21/11/12. https://doi.org/10.4028/www.scientific.net/AMM.225.109
Harun, Zambri ; Isa, Mohamad Dali ; Mohammad Rasani, Mohammad Rasidi ; Abdullah, Shahrir. / The effects of spatial resolution in turbulent boundary layers with pressure gradients. Applied Mechanics and Materials. Vol. 225 2012. pp. 109-117 (Applied Mechanics and Materials).
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