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Direct Numerical Simulations of Thermal Convection over a Wavy Surface

Krettenauer, K. and Schumann, U. (1989) Direct Numerical Simulations of Thermal Convection over a Wavy Surface. Meteorological and Atmospheric Physics, 41, pp. 165-179. DOI: 10.1007/BF01043135.

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Official URL: http://www.springerlink.com/content/0177-7971

Abstract

The influence of a wavy surface on thermal convection of Rayleigh-Bénard type in a Boussinesq fluid is investigated by direct numerical simulations. The surface height varies sinusoidally in one direction. The wave amplitude amounts up to 10% of the fluid layer height and the wavelength equals about the critical wavelength of Rayleigh-Bénard convection. The horizontal size of the computational domain equals this wavelength. For isothermal no-slip boundaries, two-dimensional convection sets in at subcritical Rayleigh numbers in close agreement with linear theory. The heat-transfer rate grows almost with the square of the surface-wave amplitude. Convection in a fluid layer over a no-slip surface with prescribed heat flux and an adiabatic free-slip boundary at the top is investigated for supercritical Rayleigh numbers and a Prandtl number of 0.7 in two and three dimensions. Two-dimensional simulations show oscillatory roll convection which becomes almost stationary if the Rayleigh number is of order 7000 or less. The two-dimensional convection is unstable with respect to three-dimensional disturbances and a cross-role pattern evolves even over a surface which is undulated in one direction only. For Rayleigh numbers exceeding about 15 000, the flow becomes turbulent. The results exhibit little sensitivity of the convection to the wavy surface for a 10% amplitude.

Document Type:Article
Title:Direct Numerical Simulations of Thermal Convection over a Wavy Surface
Authors:
AuthorsInstitution or Email of Authors
Krettenauer, K.UNSPECIFIED
Schumann, U.UNSPECIFIED
Date:1989
Journal or Publication Title:Meteorological and Atmospheric Physics
Volume:41
DOI:10.1007/BF01043135
Page Range:pp. 165-179
Status:Published
Keywords:numerical simulations, Rayleigh-Bénard convection
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Space (old)
HGF - Program Themes:W EO - Erdbeobachtung
DLR - Research area:Space
DLR - Program:W EO - Erdbeobachtung
DLR - Research theme (Project):W - Vorhaben Atmosphären- und Klimaforschung (old)
Location: Oberpfaffenhofen
Institutes and Institutions:Institute of Atmospheric Physics
Deposited By: elib DLR-Beauftragter
Deposited On:02 Apr 2006
Last Modified:12 Dec 2013 20:14

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