Effect of System Rotation on Energy Transfer of Homogeneous Decaying Turbulence.

Abstract

The effect of system rotation on energy spectrum, energy transfer function and triadic energy transfer function is investigated using the DNS data of homogeneous decaying turbulence subjected to system rotation. The DNS is performed with 128 Fourier modes at various rotation rate up to 50[rad/s]. The initial Taylor micro-scale Reynolds number is 53.6. The results of this study are summarized as follows : (1) The profile of the energy spectrum approaches the linealized solution with an increase in the rotation. That is, the decay of the energy spectrum is inhibited and promoted in low and high wave number regions, respectively, by the rotation. The absolute value of the energy transfer function decreases with an increase in the rotation. This phenomena is explained by scrambling effect. (2) The rotation gives the directional anisotropy on the energy spectrum and energy transfer function. However the effect of the directional anisotropy on the energy spectrum becomes negligible when the rotation rate is too high. (3) The triadic energy transfer is also prevented by the rotation. The local energy transfer is dominant in the non-local triad for both rotating and non-rotating systems. The rotation also gives the directional anisotropy on the triadic energy transfer function.