A method to measure spatial fluid flow components and their velocity profiles in a number of locations in a cross-sectional area of a lumen or other body cavity by using ultrasound in which the cross-sectional area is interrogated by a plurality of ultrasonic beams; the estimation of the spatial flow components is obtained from a combination of estimations of axial, lateral and total flow; the estimation of one or more flow components is obtained through any combination of time-shift and decorrelation analysis of two or more beam-signals of the interrogating ultrasound transducer; and the estimation accuracy is further improved by the use of a reference decorrelation curve obtained from experiments or beam-theory or both.