Left: Flow in a pipe. At high velocities, the flow is turbulent, and at intermediate velocities, transitional. The transitional flow is a mix of eddying flows and laminar flows. The eddying flows come in different varieties. "Slugs" grow aggressively as they flow downstream; "Puffs" maintain a fixed size as they flow downstream. Right: schematic of energy spectra corresponding to the flow inside the marked regions. Regardless of the flow variety, the energy spectrum is universal for small eddies.