Wall-pressure fluctuations in an axisymmetric boundary layer under strong adverse pressure gradient

Simple item page
dc.contributor.authorBalantrapu, N. Agastyaen
dc.contributor.authorAlexander, W. Nathanen
dc.contributor.authorDevenport, Williamen
dc.date.accessioned2023-09-11T17:37:49Zen
dc.date.available2023-09-11T17:37:49Zen
dc.date.issued2023-04en
dc.description.abstractMeasurements of fluctuating wall pressure in a high-Reynolds-number flow over a body of revolution are described. With a strong axial pressure gradient and moderate lateral curvature, this non-equilibrium flow is relevant to marine applications as well as short-haul urban transportation. The wall-pressure spectrum and its scaling are discussed, along with its relation to the space-time structure. As the flow decelerates downstream, the root-mean-square level of the pressure drops together with the wall shear stress (t(w)) and is consistently approximately 7t(w). While the associated dimensional spectra see a broadband reduction of over 15 dB per Hz, they appear to attain a single functional form, collapsing to within 2 dB when normalized with the wall-wake scaling where t(w) is the pressure scale and U-e/d is the frequency scale. Here, d is the boundary layer thickness and U-e is the local free-stream velocity. The general success of the wall-wake scaling, including in the viscous f(-5) region, suggests that the large-scale motions in the outer layer play a predominant role in the near-wall turbulence and wall pressure. On investigating further, we find that the instantaneous wall-pressure fluctuations are characterized by a quasi-periodic feature that appears to convect downstream at speeds consistent with the outer peak in the turbulence stresses. The conditional structure of this feature, estimated through peak detection in the time series, resembles that of a roller, supporting the embedded shear layer hypothesis (Schatzman & Thomas, J. Fluid Mech., vol. 815, 2017, pp. 592-642; Balantrapu et al., J. Fluid Mech., vol. 929, 2021, A9). Therefore, the outer-region shear-layer-type motions may be important when devising strategies for flow control, drag and noise reduction for decelerating boundary layers.en
dc.description.notesThis research was sponsored by the Office of Naval Research through grants N00014-17-1-2698 and N00014-20-1-2650, with Drs K.-H. Kim, J. Muench and J. Young as programme managers.en
dc.description.sponsorshipOffice of Naval Research [N00014-17-1-2698, N00014-20-1-2650]en
dc.description.versionPublished versionen
dc.format.mimetypeapplication/pdfen
dc.identifier.doihttps://doi.org/10.1017/jfm.2023.225en
dc.identifier.eissn1469-7645en
dc.identifier.issn0022-1120en
dc.identifier.otherA28en
dc.identifier.urihttp://hdl.handle.net/10919/116258en
dc.identifier.volume960en
dc.language.isoenen
dc.publisherCambridge University Pressen
dc.rightsCreative Commons Attribution 4.0 Internationalen
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/en
dc.subjectboundary layer structureen
dc.subjectaeroacousticsen
dc.titleWall-pressure fluctuations in an axisymmetric boundary layer under strong adverse pressure gradienten
dc.title.serialJournal of Fluid Mechanicsen
dc.typeArticle - Refereeden
dc.type.dcmitypeTexten

Files

Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
wall-pressure-fluctuations.pdf
Size:
4.02 MB
Format:
Adobe Portable Document Format
Description:
Published version
Download

Collections

Scholarly Works, Aerospace and Ocean Engineering