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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

DNS STUDY FOR CHARACTERISTICS AND STRUCTURES OF COMBINED-CONVECTION TURBULENT BOUNDARY LAYER ALONG VERTICAL FLAT PLATE

Get access (open in a dialog) DOI: 10.1615/IHTC16.cov.023921
pages 3403-3410

Аннотация

The objective of this study is to investigate and reveal turbulent characteristics and structures in a combined- convection turbulent boundary layer along heated or cooled vertical flat plate by means of the direct numerical simulation (DNS). Since the buoyancy directly works the streamwise velocity in a combined-convection turbulent boundary layer along vertical flat plate, it is considered that characters and structures of turbulent heat transfer of that indicate a different tendency as compared with a combined-convection turbulent boundary layer along horizontal flat plate. As results of DNS, the tendency of local wall friction coefficients in case of heated vertical flat plate (Θw > Θ0) is similar with case of unstable horizontal flat plate, and the tendency of that in case of cooled vertical flat plate (Θw < Θ0) is similar with case of stable horizontal flat plate. On the other hand, the tendencies of distribution of local Stanton number indicate different tendencies in comparison with the tendencies of cases of horizontal flat plate. Therefore, the similarity between velocity and thermal fields is not maintained in case of a combined-convection turbulent boundary layer along vertical flat plate. Also, DNS clearly shows the variations of turbulent statistics and turbulent structures like as streaky and vortex structures in a combined-convection turbulent boundary layer along heated or cooled vertical flat plate. As the mentioned above, by investigating and observing a combined-convection turbulent boundary layer along heated or cooled vertical flat plate having the entrance region of thermal field using DNS, the turbulent heat transfer characteristics and structures can be revealed.