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Length of near-wall plumes in turbulent convection

Puthenveettil, Baburaj A. und Gunasegarane, G. S. und Agrawal, Yogesh K. und Schmeling, Daniel und Bosbach, Johannes und Arakeri, Jaywant H. (2011) Length of near-wall plumes in turbulent convection. Journal of Fluid Mechanics, Vol. 6, Seiten 335-364. Cambridge University Press. DOI: 10.1017/jfm.2011.319. ISSN 0022-1120.

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Offizielle URL: http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8384309&fulltextType=RA&fileId=S0022112011003193

Kurzfassung

We present planforms of line plumes formed on horizontal surfaces in turbulent convection, along with the length of line plumes measured from these planforms, in a six decade range of Rayleigh numbers (10^5 < Ra < 10^11) and at three Prandtl numbers (Pr= 0.7, 5.2, 602). Using geometric constraints on the relations for the mean plume spacings, we obtain expressions for the total length of near-wall plumes on horizontal surfaces in turbulent convection. The plume length per unit area (L_p / A), made dimensionless by the near-wall length scale in turbulent convection (Z_w), remains constant for a given fluid. The Nusselt number is shown to be directly proportional to L_p H/ A for a given fluid layer of height H. The increase in Pr has a weak influence in decreasing L_p / A. These expressions match the measurements, thereby showing that the assumption of laminar natural convection boundary layers in turbulent convection is consistent with the observed total length of line plumes. We then show that similar relationships are obtained based on the assumption that the line plumes are the outcome of the instability of laminar natural convection boundary layers on the horizontal surfaces.

Dokumentart:Zeitschriftenbeitrag
Zusätzliche Informationen:Published online: 20. September 2011
Titel:Length of near-wall plumes in turbulent convection
Autoren:
AutorenInstitution oder E-Mail-Adresse der Autoren
Puthenveettil, Baburaj A.Department od Applied Mechanics, Indian Institute of Technology Madras, Chennai, India
Gunasegarane, G. S.Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai, India
Agrawal, Yogesh K.Department of Mechanical Engineering, National Institute of Technology, Durgapur, India
Schmeling, DanielNICHT SPEZIFIZIERT
Bosbach, JohannesNICHT SPEZIFIZIERT
Arakeri, Jaywant H.Department of Mechanical Engineering, Indian Institute of Science, Bangalore, India
Datum:2011
Erschienen in:Journal of Fluid Mechanics
Referierte Publikation:Ja
In Open Access:Nein
In SCOPUS:Ja
In ISI Web of Science:Ja
Band:Vol. 6
DOI :10.1017/jfm.2011.319
Seitenbereich:Seiten 335-364
Verlag:Cambridge University Press
ISSN:0022-1120
Status:veröffentlicht
Stichwörter:buoyant boundary layers, plumes/thermals, turbulent convection
HGF - Forschungsbereich:Luftfahrt, Raumfahrt und Verkehr
HGF - Programm:Luftfahrt
HGF - Programmthema:Starrflügler
DLR - Schwerpunkt:Luftfahrt
DLR - Forschungsgebiet:L AR - Starrflüglerforschung
DLR - Teilgebiet (Projekt, Vorhaben):L - Flugphysik
Standort: Göttingen
Institute & Einrichtungen:Institut für Aerodynamik und Strömungstechnik > Fluidsysteme
Hinterlegt von: Daniel Schmeling
Hinterlegt am:23 Sep 2011 11:15
Letzte Änderung:12 Dez 2013 21:16

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