| Tue October 25th 2011 16:00 HT 500B | Seminar | PDF Equation Approach to Temperature Statistics in Turbulent Rayleigh-Bénard Convection Johannes Lülff |
Details:Rayleigh-Bénard convection, i.e. the convection of a fluid enclosed between two plates that is driven by a temperature gradient,is the idealized setup of a phenomenon ubiquitous in nature and technical applications. Of special interest for this system are the statistics of temperature fluctuations, which we are investigating in the turbulent regime. To this end, we derive an exact evolution equation for the probability density function (PDF) of temperature from first principles. Appearing unclosed terms are expressed as conditional averages of vertical velocity and heat diffusion, which are estimated from direct numerical simulations. Our theoretical framework allows to connect these statistical quantities to the dynamics of Rayleigh-Bénard convection, giving deeper insights into the temperature statistics and transport mechanisms in different regions of the fluid volume, i.e. in the boundary layers and the bulk. | ||
