Turbulence around heat transport
Not only in the Earth's mantle, in the atmosphere and in the outer layers of the Sun, but also in a chemical reactor, the exchange of heat may not be as effective as originally thought. There, because warm fluid rises and hence induces movement, the turbulent convection can be 100 billion times stronger than in the typical cooking pot. Hot fluids mix turbulently with warm fluids. As the temperature difference between the cold and warm sides increases, the heat transport increases exponentially. When the turbulence is very strong, the exponential growth decreases twofold. Physicists from the Max Planck Institute for Dynamics and Self-Organisation, University of California at Santa Barbara, and the French Centre National de la Recherche Scientifique in Nancy report this discovery in the current issue of New Journal of Physics. The long standing theory for turbulent convective heat transport from 1962 had predicted that the exponential growth would...