Figure A.1.

Changes in area (dA), flow velocity (dU) and pressure (dP) across a pulse wavefront travelling (a,c) forward (in the positive x direction) and (b,d) backward with speeds of c + U and c − U, respectively, where c is the local pulse wave velocity. They are measured from a frame of reference fixed to the vessel (a,b) and moving with the wavefront (c,d). The dashed rectangles indicate the control volume used to derive Equations (A.2)–(A.7).