Perturbing spanwise modes in turbulent boundary layers

Shaokai Zheng, Ellen K. Longmire

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

Abstract

A single spanwise array of cylinders was used to perturb a zero pressure gradient turbulent boundary layer (Reτ=2500). The cylinder height was H/δ=0.2 (H+=500) with aspect ratio (height/diameter) of AR=4, and four cases were studied with cylinder spacing from 0.2δ to 0.8δ. Streamwise-spanwise planes were measured by particle image velocimetry (PIV) up to 7δ downstream at a wallnormal location of z+=300. The 0.6δ case, which matched the dominant spanwise mode in the unperturbed flow, showed the most stable downstream organization which persisted beyond 7δ. The cylinders were observed to sometimes enhance the organization of existing packets and to generally redirect packets into the spanwise location midway between cylinders. Approaching packets lost their organization immediately downstream of the 0.2δ array but regained it downstream, suggesting that the outer layer organization propagated inward into the log region.

Original languageEnglish (US)
Title of host publicationInternational Symposium on Turbulence and Shear Flow Phenomena, TSFP 2013
PublisherTSFP-8
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

Publication series

NameInternational Symposium on Turbulence and Shear Flow Phenomena, TSFP 2013
Volume2

Other

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

Fingerprint Dive into the research topics of 'Perturbing spanwise modes in turbulent boundary layers'. Together they form a unique fingerprint.

Cite this