The twists and turns of rotating turbulence

Abstract

Turbulence is widely considered one of the most important and most difficult unsolved problems in classical physics. It is also the area of fluid mechanics where the greatest effort is exerted, the most papers published and, some would argue, the least progress made. Although direct numerical simulation is becoming an increasingly valuable tool, there remains a need for high-quality experiments to underpin our theoretical and numerical progress. Such statements apply equally to the ‘classical’ problem of homogeneous isotropic turbulence and to turbulence in its many other guises. Of particular interest is turbulence in a rotating system, where it is well known that the influence of rotation leads to the development of anisotropy and the elongation of scales parallel to the rotation axis. Moisy et al. (J. Fluid Mech., 2010, this issue, vol. 666, pp. 5–35) present new experiments in the free decay of grid-generated turbulence in a rotating system. They investigate the emergence of anisotropy from essentially isotropic initial conditions. While it is well known that rotation suppresses velocity gradients parallel to the rotation axis, Moisy et al. (2010) uncover some startling and previously overlooked implications.

Coherent Structures and Extreme Events in Rotating Multiphase Turbulent Flows

“…The most striking phenomenon originated by the Coriolis force is the formation of intense and coherent columnar vortical structures (see Fig. 1), which has been observed in numerical simulations [15][16][17][18][19] and in experiments for rotating turbulence produced by an oscillating grid [9], for decaying turbulence [10][11][12], forced turbu-lence [14], and turbulent convection [24]. The appearance of these large-scale vortices is associated to a noticeable two-dimensionalization of the flow in the plane perpendicular to the rotation axis.…”

“…The dynamics of fluids under strong rotation is a challenging problem in the field of hydrodynamics and magnetohydrodynamics [1,2], with key applications to geophysical and astrophysical problems (oceans, Earth's atmosphere and inner mantle, gaseous planets, planetesimal formations) and engineering (turbomachinery, chemical mixers) [3][4][5][6][7][8]. A considerable number of experiments [9][10][11][12][13][14][15][16][17][18][19][20][21][22] have been devoted to investigating how turbulence is affected by rotation (for a recent review of experimental and numerical results see Ref. [23]).…”

Structure and Dynamics of Rotating Turbulence: A Review of Recent Experimental and Numerical Results

“…4 for freely decaying turbulence in experiments [32,33,64] and direct numerical simulations [61,65], but also in forced rotating turbulence at various resolutions [57,59]. The quantitative statistical characterization of the elongation of structures can be done using the length scales associated with directional two-point velocity correlations…”