Understanding the energy cascade in turbulent flows is a hard problem because of two difficulties : complex physics and inadequate tools. While there is marginal disagreement on the complexity of the cascade, we are generally less prolific on the subject of tool inadequacy. Yet it may be the tools we choose that lead to an incomplete understanding of the underlying phenomena, and not the complexity of the problem itself. In this talk, I will present three studies of the energy cascade in homogeneous and incompressible flows, including shear flows. The advantages and the shortcomings of each approach will be highlighted.
Figure 1. Flow regions of intense kinetic energy contained at four different scales Δ in terms of the Kolmogorv length scale η. Homogeneous isotropic turbulence, Re λ = 315. From Cardesa, J.I., Vela-Martín, A. and Jiménez, J., 2017. Science, 357, pp. 782-784.
