Effects of roughness elements on the separation of laminar boundary layers

N. Beratlis, A. Vizard, Kyle Squires, E. Balaras

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

Abstract

A series of direct numerical simulations (DNS) of the flow past a zero pressure gradient flat plate with rows of dimples is carried out. The Reynolds number based on the boundary layer thickness is 1000 and the dimples have a circular profile with a depth to diameter ratio of 0.1. The incoming flow is laminar and the ratio of the incoming boundary layer thickness to the dimple depth determines the critical Reynolds number, where transition to turbulence occurs downstream. This happens as the shear layer that forms at the dimple edge separates over the first row of dimples and becomes unstable creating coherent vortex sheet. The vortex sheet undergoes a complex spanwise instability transforming themselves into a packet of horseshoe vortices. As a result the boundary layer downstream of the dimples has the same qualitative features encountered in wall bounded turbulent boundary layers.

Original languageEnglish (US)
Title of host publicationInternational Symposium on Turbulence and Shear Flow Phenomena, TSFP 2013
PublisherTSFP-8
Volume1
ISBN (Electronic)9780000000002
StatePublished - Jan 1 2013
Event8th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2013 - Poitiers, France
Duration: Aug 28 2013Aug 30 2013

Other

Other8th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2013
CountryFrance
CityPoitiers
Period8/28/138/30/13

ASJC Scopus subject areas

  • Fluid Flow and Transfer Processes

Fingerprint Dive into the research topics of 'Effects of roughness elements on the separation of laminar boundary layers'. Together they form a unique fingerprint.

  • Cite this

    Beratlis, N., Vizard, A., Squires, K., & Balaras, E. (2013). Effects of roughness elements on the separation of laminar boundary layers. In International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2013 (Vol. 1). TSFP-8.