Figure 9

3D (equation ( 10 ), blue) and 2D, transverse (equation ( 26 ), red) energy spectra for the PPM_HLLC simulations. The energy spectra are compensated by \(k^{5/3}\) to highlight eventual regions with Kolmogorov scaling. The spectra are plotted as a function of the dimensionless wave number \(512 k \Delta x\), as in Figure 5. Although \(E(k)\) and \(E_{\perp}(k_{\perp})\) have similar trends, the use of the transverse spectrum can overestimate the width of the bottleneck region.