Keywords: Envelope of the disturbance emitted at successive times.svg en Envelope of the disturbance emitted at successive times fig 12 3 p 410 of G B Whitham 1974 Linear and Nonlinear Waves John Wiley Sons Inc 1974 The circles represent wavefronts 2016-01-31 own Maschen other versions cc-zero SVG physics Fluid dynamics Waves Wakes fluids |