Coordinate System and Geometry of Doppler Velocimeters

It mainly consists of three parts: the measuring probe, signal conditioning, and signal processing. The measuring probe consists of three 10 MHz receiving transducers and one transmitting transducer. The three receiving transducers are distributed around the axis of the transmitting transducer, with a 120° angle between them. The angle between the line connecting the receiving transducer and the sampling volume and the axis of the transmitting transducer is 30°. The sampling volume is located 5 cm or 10 cm below the probe, which essentially eliminates the probe's interference with the flow field.

Dayu ElectronicsDoppler velocimeter coordinate system: The signal conditioner consists of analog circuits that detect weak reflected signals; digital signal processing is performed by a separate circuit board, mainly for calculating real-time three-dimensional velocity measurements at an output frequency of 25 Hz. The ADV data acquisition software uses the built-in ADF2.6, and the signals and various flow parameters are processed by WINADV. The data files it provides are text files, which can be conveniently processed by many software programs such as Excel, Matlab, and Grapher. In addition, ADV measurements adopt the same coordinate system and notation as the manufacturer, where Vx, Vy, and Vz represent the streamwise, transverse, and vertical velocities, respectively.