Characterization and testing of a new bistatic profiling acoustic Doppler velocimeter: The Vectrino-II

Pulse-to-pulse coherent Doppler sonar systems have been commercially available for almost two decades now. These systems provide non-intrusive, high accuracy, low noise data in difficult environments. Pulse coherent profilers are also capable of measuring very small cell sizes and provide far more details of flow than standard Doppler systems. Multi-beam bi-static profiling systems allow measurements of velocity over a specified range of cells with each beam providing data from closely spaced measurement volumes, thereby removing the need for assumptions of flow homogeneity as required for mono-static systems with diverging beams. While a few bi-static profiling prototype systems have been demonstrated, there have been no commercial platforms available that provide a cost-effective, turn-key solution for providing three component data profiles with accompanying display and processing software tools. This paper will describe one such system, the Nortek Vectrino-II. A description of the instrument hardware and software capabilities will be followed by a discussion of some of the novel features and algorithms used by the instrument. Tow tank data and comparisons with a PIV system will be presented.