The decay of turbulence in a bounded domain

The decay of turbulence in a bounded domain without mean velocity is investigated. Direct and large-eddy simulations, as well as the eddy-damped quasi-normal Markovian closure, are used. The effect of the finite geometry of the domain is accounted for by introducing a low-wavenumber cut-off into the energy spectrum of isotropic turbulence. It is found that, once the saturation of the turbulent energy-containing length scale has occurred, the rms vorticity decays following a power law with a −3/2 exponent, in agreement with the helium superfluid experiment of Skrbek and Stalp (Skrbek L and Stalp S R 2000 Phys. Fluids 12 1997–2019). The decay exponent for the turbulent kinetic energy is found to be −2, also in agreement with Skrbek and Stalp. Using scalings deduced from a simple analysis, all data can be collapsed into single curves for both the fixed scale turbulent regime and the final viscous period of decay. A spectral model for inhomogeneous turbulence is finally applied to the decay of turbulence between two plates. It is shown that the results are in agreement with the helium experiment. This article was chosen from Selected Proceedings of the Second International Symposium on Turbulence and Shear Flow Phenomena (KTH-Stockholm, 27-29 June 2001) ed E Lindborg, A Johansson, J Eaton, J Humphrey, N Kasagi, M Leschziner and M Sommerfeld.