کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
659887 | 1458117 | 2010 | 8 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Turbulent large-scale structures in natural convection vertical channel flow Turbulent large-scale structures in natural convection vertical channel flow](/preview/png/659887.png)
We analyzed a database of a direct numerical simulation of natural convection in a vertical channel. The flow is driven by a constant temperature difference imposed at the walls (Ra = 5.4 × 105, Pr = 0.7). The averaged flow and turbulent statistics are in good agreement with previous direct numerical simulations reported in the literature. Contrary to forced convection flows, the fluctuations of the heat transfer rate are uncorrelated with the fluctuations of the wall shear stress, which exhibit a symmetric probability density function. At the low Rayleigh number considered, the large-scale structures, which consist mainly in two counter-rotating vortices, with sizes comparable to the separation of the walls, are responsible for the extreme fluctuations of the wall heat transfer rate. The occurrence and the averaged topology of these structures have been determined using a conditional sampling technique.
Journal: International Journal of Heat and Mass Transfer - Volume 53, Issues 19–20, September 2010, Pages 4168–4175