Keylock, C.J., Ganapathasubramani, B., Monty, J. et al. (2 more authors) (2016) The coupling between inner and outer scales in a zero pressure boundary layer evaluated using a Hölder exponent framework. Fluid Dynamics Research, 48 (2). 021405. ISSN 0169-5983
Abstract
This work considers the connectivity between large and small scales in boundary-layer turbulence by formalizing the modulation effect of the small scales by the large in terms of the pointwise Hölder condition for the small scales. We re-investigate a previously published dataset from this perspective and are able to characterize the coupling effectively using the (cross-)correlative relations between the large scale velocity and the small scale Hölder exponents. The nature of this coupling varies as a function of dimensionless distance from the wall based on inner-scaling, ${y}^{+}$, as well as on the boundary-layer height, δ. In terms of the fundamental change in the sign of the coupling between large and small scales, the critical height appears to be ${y}^{+}\sim 1000$. Below this height, small scale structures are associated with (and occur earlier than) maxima in the large scale velocity. Above this height, while the lag is similar in magnitude, the small scale structures are associated with minima in the large scale velocity. To consider these results further, we introduce a modified quadrant analysis and show that it is the coupling to the large scale low velocity state that is critical for the dynamics.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © Year 2016 The Japan Society of Fluid Mechanics and IOP Publishing Ltd. This is an author produced version of a paper subsequently published in Fluid Dynamics Research. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | boundary-layer; Hölder exponents; velocity-intermittency coupling; quadrants; interscale coupling; phase relations |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Civil and Structural Engineering (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 02 Mar 2016 10:35 |
Last Modified: | 14 Apr 2017 03:28 |
Published Version: | http://dx.doi.org/10.1088/0169-5983/48/2/021405 |
Status: | Published |
Publisher: | IOP Publishing |
Refereed: | Yes |
Identification Number: | 10.1088/0169-5983/48/2/021405 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:95858 |