Run B. Turbulence with expansion and no mean field: spectra vs. k_R (radial wavenumber, i.e., in direction parallel to the mean radial flow) at t = 0.8,1.2,...3.2 nonlinear times (vertical arrows indicate direction of time evolution). a) Total energy spectra compensated by k^{− 5/3}; b) residual energy, compensated by k^-2; c) residual energy normalized by the α = 1 prediction; d) residual energy normalized by the α = 2 prediction (see Eq. (15)).