Ultrasonic Doppler method was initially developed in medical engineering for clinical use. It was intended to measure a vascular flow in cardiology. The system was developed so to date and has been improved to make a flow map of heart. It is still used for diagnosing purpose in many hospitals.
The medical system of UVP is however not adequate for general fluid mechanical study, since such a system adopts a variety of tricks of signal processing and algorithms in order to overcome several difficulties arising from the fact that it is used for human body. A few examples; usually a signal to noise ratio of the original echo is very poor due to a condition of reflectors in blood. High voltage application to the transducer is limited by safety reason and regulations. More can be cited than its negligible need for high accuracy and high resolution in space and time domain.
The UVP for general fluid mechanical study was developed at the Paul Scherrer Institute (PSI), Villigen, Switzerland. The work was started by Y.Takeda, Dr. in collaboration with J.J.Meister, Dr (now Proffesor of EPFL, Medical Engineering) in 1983, who built the first system similar to the medical equipment.
The motivation for PSI to invent the new measuring method and developed the UVP system was that they needed to study the flow of liquid metal for the target of Spallation Neutron Source, SINQ. It has been approved, however, that UVP is very powerful and probably the only possible method for studying thermalhydaulic behavior of liquid metals.
The patent has been granted for worldwide to NOVATEC SA, presently Met-Flow SA, who are now marketing the device.