title: Fractal space-scale unfolding mechanism for energy-efficient turbulent mixing.
abstract: Using top-end high fidelity computer simulations we demonstrate the existence of a mechanism present in turbulent flows generated by multiscale or fractal objects and which has its origin in the multiscale or fractal space-scale structure of such turbulent flow generators. As a result of this space-scale unfolding mechanism, fractal grids can enhance scalar transfer and turbulent diffusion by one order of magnitude while at the same time reduce pressure drop by half. This mechanism must be playing a decisive role in environmental, atmospheric, ocean, and river transport processes wherever turbulence originates from multiscale or fractal objects such as trees, forests, mountains, rocky riverbeds, and coral reefs. It also ushers in the concept of fractal design of turbulence which may hold the power of setting entirely new mixing and cooling industrial standards.
authors.affiliation: Turbulence, Mixing and Flow Control Group, Department of Aeronautics, South Kensington, Imperial College, London SW7 2BZ, United Kingdom. s.laizet@imperial.ac.uk
authors.forename: S
authors.initials: S
authors.lastname: Laizet
authors.forename: J C
authors.initials: JC
authors.lastname: Vassilicos