The aim of this research study is to develop a flexible ultrasound transducer capable of determining the blood volume flow. Currently, there are a few different methods of measuring fluid flow inside a vessel using ultrasound. In Doppler shift and time transit flowmeters, a wedge has been used to mount a piezoelectric transducer in order to create a known angle between the direction of fluid flow and the direction of generated wave propagation. In general, the flat nature of piezoelectric transducers has restricted the application of this method to mounting surfaces with known geometry. However, in a recent study, a flexible piezo-composite ultrasonic transducer was developed using PZT-5H and a passive polymer matrix (PDMS). Due to the flexibility of this unique transducer, it can be mounted on surfaces of unknown and varying geometry. In the context of measuring the blood flow rate in a human vessel, the transducer can be integrated into a wearable device capable of determining the orientation and position of the vessel’s path using wave time of flight. In this article, we measured a flow speed using the flexible transducer embedded on a curved surface of a tissue-mimicking material, in which water flows through an artificial flow vessel aligned in a known angular direction. Then, the velocity of the flowing medium in the vessel is estimated by using the Doppler shift method. The experimental results will provide the fundamental background for application of the flexible transducer to the wearable device capable of measuring the blood flow and the pressure.