Fluid flow analysis

A method of determining a measure of wave intensity in a fluid conduit, the method comprising:

• using ultrasound measurements to determine the conduit diameter, as a function of time, at a longitudinal position of the conduit;
• using ultrasound measurements to determine a measure of fluid velocity, as a function of time, in a volume element at said longitudinal position of the conduit, the ultrasound measurements to determine the measure of fluid velocity being effected by decorrelation of scattering objects within the fluid flow in successive frames sampling the volume element, in which the measure of fluid velocity is determined using speckle decorrelation velocimetry, in which ultrasound signals for the speckle decorrelation velocimetry are optimized using RF data filtering, in which the ultrasound measurements for determining conduit diameter and fluid velocity are both obtained from imaging a single line across the fluid conduit;
• determining, through wave intensity analysis, a measure of wave intensity as a function of change in determined conduit diameter and corresponding change in the measure of fluid velocity,
• wherein the method is non-invasive, and
• wherein the measure of wave intensity is determined according to the equation ndI=dDdU, where ndl is the wave intensity determined from non-invasive measurements;
• dD is the change of conduit diameter;
• and dU is the change of the measure of fluid velocity.