No Cover Image

Journal article 173 views

Numerical simulation of the spatiotemporal development of linear disturbances in Stokes layers: Absolute instability and the effects of high-frequency harmonics

Xander Ramage, Christopher Davies, Christian Thomas, Michael Togneri Orcid Logo

Physical Review Fluids, Volume: 5, Issue: 10

Swansea University Authors: Xander Ramage, Michael Togneri Orcid Logo

Full text not available from this repository: check for access using links below.

Check full text

DOI (Published version): 10.1103/physrevfluids.5.103901

Abstract

For a family of oscillatory Stokes layers, the spatiotemporal evolution of impulsively excited disturbances is investigated, using direct numerical simulations of the linearized Navier-Stokes equations. The semi-infinite planar Stokes layer is modified to incorporate a low-amplitude, high-frequency...

Full description

Published in: Physical Review Fluids
ISSN: 2469-990X
Published: American Physical Society (APS) 2020
Online Access: Check full text

URI: https://cronfa.swan.ac.uk/Record/cronfa55533
Tags: Add Tag
No Tags, Be the first to tag this record!
first_indexed 2020-10-28T09:18:58Z
last_indexed 2020-12-05T04:09:40Z
id cronfa55533
recordtype SURis
fullrecord <?xml version="1.0"?><rfc1807><datestamp>2020-12-04T17:53:13.4260601</datestamp><bib-version>v2</bib-version><id>55533</id><entry>2020-10-28</entry><title>Numerical simulation of the spatiotemporal development of linear disturbances in Stokes layers: Absolute instability and the effects of high-frequency harmonics</title><swanseaauthors><author><sid>5fc043d595817fc00de1d606af37206e</sid><firstname>Xander</firstname><surname>Ramage</surname><name>Xander Ramage</name><active>true</active><ethesisStudent>false</ethesisStudent></author><author><sid>7032d5a521c181cea18dbb759e1ffdeb</sid><ORCID>0000-0002-6820-1680</ORCID><firstname>Michael</firstname><surname>Togneri</surname><name>Michael Togneri</name><active>true</active><ethesisStudent>false</ethesisStudent></author></swanseaauthors><date>2020-10-28</date><deptcode>EEN</deptcode><abstract>For a family of oscillatory Stokes layers, the spatiotemporal evolution of impulsively excited disturbances is investigated, using direct numerical simulations of the linearized Navier-Stokes equations. The semi-infinite planar Stokes layer is modified to incorporate a low-amplitude, high-frequency harmonic, which provides a simplified model of the external noise found in physical experiments. For the unmodified Stokes layer, impulsively excited disturbances are known to form family-tree-like structures, composed of multiple wave packets. The long-term behavior that is encompassed within these structures is studied, together with the effects upon them of the alterations to the base flow. In the absence of any base-flow modification, the disturbances are discovered to exhibit a subharmonic pattern of temporal growth, with a periodicity that is twice that of the basic state. It is also shown that when linear instability first arises, it takes an absolute rather than a convective form. Inclusion of a high-frequency harmonic into the basic state is found to have a strong and destabilizing impact upon the impulse response. The development of the family-tree-like disturbance structure can be disrupted, changing the character of the absolute instability and promoting its appearance at much reduced Reynolds numbers.</abstract><type>Journal Article</type><journal>Physical Review Fluids</journal><volume>5</volume><journalNumber>10</journalNumber><paginationStart/><paginationEnd/><publisher>American Physical Society (APS)</publisher><placeOfPublication/><isbnPrint/><isbnElectronic/><issnPrint/><issnElectronic>2469-990X</issnElectronic><keywords/><publishedDay>2</publishedDay><publishedMonth>10</publishedMonth><publishedYear>2020</publishedYear><publishedDate>2020-10-02</publishedDate><doi>10.1103/physrevfluids.5.103901</doi><url>http://orca.cf.ac.uk/135864/</url><notes/><college>COLLEGE NANME</college><department>Engineering</department><CollegeCode>COLLEGE CODE</CollegeCode><DepartmentCode>EEN</DepartmentCode><institution>Swansea University</institution><apcterm/><lastEdited>2020-12-04T17:53:13.4260601</lastEdited><Created>2020-10-28T09:17:57.1114291</Created><path><level id="1">Faculty of Science and Engineering</level><level id="2">School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Mechanical Engineering</level></path><authors><author><firstname>Xander</firstname><surname>Ramage</surname><order>1</order></author><author><firstname>Christopher</firstname><surname>Davies</surname><order>2</order></author><author><firstname>Christian</firstname><surname>Thomas</surname><order>3</order></author><author><firstname>Michael</firstname><surname>Togneri</surname><orcid>0000-0002-6820-1680</orcid><order>4</order></author></authors><documents/><OutputDurs/></rfc1807>
spelling 2020-12-04T17:53:13.4260601 v2 55533 2020-10-28 Numerical simulation of the spatiotemporal development of linear disturbances in Stokes layers: Absolute instability and the effects of high-frequency harmonics 5fc043d595817fc00de1d606af37206e Xander Ramage Xander Ramage true false 7032d5a521c181cea18dbb759e1ffdeb 0000-0002-6820-1680 Michael Togneri Michael Togneri true false 2020-10-28 EEN For a family of oscillatory Stokes layers, the spatiotemporal evolution of impulsively excited disturbances is investigated, using direct numerical simulations of the linearized Navier-Stokes equations. The semi-infinite planar Stokes layer is modified to incorporate a low-amplitude, high-frequency harmonic, which provides a simplified model of the external noise found in physical experiments. For the unmodified Stokes layer, impulsively excited disturbances are known to form family-tree-like structures, composed of multiple wave packets. The long-term behavior that is encompassed within these structures is studied, together with the effects upon them of the alterations to the base flow. In the absence of any base-flow modification, the disturbances are discovered to exhibit a subharmonic pattern of temporal growth, with a periodicity that is twice that of the basic state. It is also shown that when linear instability first arises, it takes an absolute rather than a convective form. Inclusion of a high-frequency harmonic into the basic state is found to have a strong and destabilizing impact upon the impulse response. The development of the family-tree-like disturbance structure can be disrupted, changing the character of the absolute instability and promoting its appearance at much reduced Reynolds numbers. Journal Article Physical Review Fluids 5 10 American Physical Society (APS) 2469-990X 2 10 2020 2020-10-02 10.1103/physrevfluids.5.103901 http://orca.cf.ac.uk/135864/ COLLEGE NANME Engineering COLLEGE CODE EEN Swansea University 2020-12-04T17:53:13.4260601 2020-10-28T09:17:57.1114291 Faculty of Science and Engineering School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Mechanical Engineering Xander Ramage 1 Christopher Davies 2 Christian Thomas 3 Michael Togneri 0000-0002-6820-1680 4
title Numerical simulation of the spatiotemporal development of linear disturbances in Stokes layers: Absolute instability and the effects of high-frequency harmonics
spellingShingle Numerical simulation of the spatiotemporal development of linear disturbances in Stokes layers: Absolute instability and the effects of high-frequency harmonics
Xander Ramage
Michael Togneri
title_short Numerical simulation of the spatiotemporal development of linear disturbances in Stokes layers: Absolute instability and the effects of high-frequency harmonics
title_full Numerical simulation of the spatiotemporal development of linear disturbances in Stokes layers: Absolute instability and the effects of high-frequency harmonics
title_fullStr Numerical simulation of the spatiotemporal development of linear disturbances in Stokes layers: Absolute instability and the effects of high-frequency harmonics
title_full_unstemmed Numerical simulation of the spatiotemporal development of linear disturbances in Stokes layers: Absolute instability and the effects of high-frequency harmonics
title_sort Numerical simulation of the spatiotemporal development of linear disturbances in Stokes layers: Absolute instability and the effects of high-frequency harmonics
author_id_str_mv 5fc043d595817fc00de1d606af37206e
7032d5a521c181cea18dbb759e1ffdeb
author_id_fullname_str_mv 5fc043d595817fc00de1d606af37206e_***_Xander Ramage
7032d5a521c181cea18dbb759e1ffdeb_***_Michael Togneri
author Xander Ramage
Michael Togneri
author2 Xander Ramage
Christopher Davies
Christian Thomas
Michael Togneri
format Journal article
container_title Physical Review Fluids
container_volume 5
container_issue 10
publishDate 2020
institution Swansea University
issn 2469-990X
doi_str_mv 10.1103/physrevfluids.5.103901
publisher American Physical Society (APS)
college_str Faculty of Science and Engineering
hierarchytype
hierarchy_top_id facultyofscienceandengineering
hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Mechanical Engineering{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Mechanical Engineering
url http://orca.cf.ac.uk/135864/
document_store_str 0
active_str 0
description For a family of oscillatory Stokes layers, the spatiotemporal evolution of impulsively excited disturbances is investigated, using direct numerical simulations of the linearized Navier-Stokes equations. The semi-infinite planar Stokes layer is modified to incorporate a low-amplitude, high-frequency harmonic, which provides a simplified model of the external noise found in physical experiments. For the unmodified Stokes layer, impulsively excited disturbances are known to form family-tree-like structures, composed of multiple wave packets. The long-term behavior that is encompassed within these structures is studied, together with the effects upon them of the alterations to the base flow. In the absence of any base-flow modification, the disturbances are discovered to exhibit a subharmonic pattern of temporal growth, with a periodicity that is twice that of the basic state. It is also shown that when linear instability first arises, it takes an absolute rather than a convective form. Inclusion of a high-frequency harmonic into the basic state is found to have a strong and destabilizing impact upon the impulse response. The development of the family-tree-like disturbance structure can be disrupted, changing the character of the absolute instability and promoting its appearance at much reduced Reynolds numbers.
published_date 2020-10-02T04:09:49Z
_version_ 1763753684247773184
score 11.01438

Similar Items