A device for blood flow measurement within a vascular vessel or within the heart comprises two transducers (2,3) mounted at the surface of a catheter (1). One (2) of the transducers has a protrusion (fixed or glued) with a hydrofoil profile (underwater wing), while the other transducer (3) has a cylindrical profile.
On the hydrofoil transducer, the signal is generated by the surrounding quasi-static pressure and the drag force induced by the blood flow. On the other transducer, the signal is generated only by the quasi-static pressure. Either by connecting the transducers in a differential manner or by taking their signals to a differential amplifier, the signal caused by the axial flow velocity is obtained.