Abstract
Direct numerical simulations of turbulent Rayleigh–Bénard convection have been conducted in large aspect ratio boxes to examine the characteristics of convection in the range of Rayleigh numbers corresponding to the soft turbulence regime in the Chicago group classification. A measured exponent in the power law dependence of Nusselt number on Rayleigh number is 0.274, closer to the value 2/7 found in a small aspect ratio cell at the University of Chicago for the hard turbulence regime than the 1/3 obtained there for soft turbulence. The distributions of temperature fluctuation T′ in the convective core do not exhibit a unique functional form. Gaussian, exponential, and mixed (Gaussian-exponential) forms are observed. Further, it is shown that a transition in the functional form of the T′ pdf can be produced by changing the aspect ratio of the computational box without changing Rayleigh number at all. These results are in agreement with other studies, which have indicated that the hard/soft characterization of turbulent convection may partially reflect as yet not fully understood distinctions between convective turbulence in large and small aspect ratio cells.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
