Top panel: temporal evolution of the Fourier coefficient with p = 0 (red solid line) and of the sum of the modulus of the first twenty positive Fourier coefficients (blue dashed line). For this analysis, the azimuthal component of velocity along a circle of radius 1.3R at the z = 0 plane is used. The two vertical dashed black lines show, respectively, the onset of the KHI obtained from this Fourier analysis, τ_KH ≈ 70, and the time at which the KHI is first seen to grow in the density, τ_vis = 280. Bottom panel: same as the top panel but for the radial component of velocity.