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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Direct Numerical Simulation on the Effects of Amplitude and Hydrophilicity of Wavy Wall on Turbulent Heat Transfer and Drag

Get access (open in a dialog) DOI: 10.1615/IHTC15.ttr.009788
pages 9243-9256

Sinopsis

In this study, we have carried out direct numerical simulation for turbulent flow in a channel whose heating walls are sinusoidal wavy-shaped. The ratio of amplitude to wavelength is set low enough to avoid the separation and reattachment of flow. Moreover, we have dealt with slightly slippery surfaces which are expected to reduce frictional drag. The computational results show that the friction drag in the case of the slippery surfaces is much higher than that in the case of non-slip surface while the Nusselt number in the case of the slippery surfaces is slightly higher than that in the case of non-slip surfaces. This difference is due to the fact that the slip surface affects only the velocity field in the vicinity of the surface because of the low slip velocity. It is also found that the frictional drag decreases with an increase in the amplitude of the wavy walls, while the Nusselt number increases with the increase in the amplitude. This increase in the Nusselt number is due to a decrease in the mean temperature profile, which is caused by a decrease in the turbulent heat flux in the buffer region.