Author(s): Marie Burckbuchler; Stephane Fischer
Keywords: Ultrasonic Velocity Profiler; Portable; Autonomous; Physical Model
Abstract: As Ubertone’s first goal is to bring the UVP technology to more users and applications, we follow several RTD axes. One axis concerns the multiplication of measured velocity components along a profile, while keeping a high space-time resolution, which led to the UB-Lab 2C, launched in 2018, a commercial ADVP (Acoustic Doppler Velocity Profilers). Another axis is mobility and easy installation with miniaturisation and autonomy. First UVPs were of the size of PC towers. Ubertone released its first compact laboratory UVP in 2011, the UB-Lab. Continuing in this direction, we launched last september 2020 the UB-Lab P, the world's first handheld UVP, a ready-to-use battery-powered instrument, with an embedded web-interface accessed by wifi. This presentation will focus on the UB-Lab P, with an application example on a physical model of a river section. The UB-Lab P with external power bank is attached to the carriage, which sends trigger signals to the UB-Lab P when measurements need to be recorded. Two diverging transducers allow to get average two-component velocity profiles, and a motor on the transducer holder allows choosing between U/W or U/V orientation. The first routine was to scan several transects and record continuously during the displacement, the trigger was set to low when transiting between transects. The carriage positions are recorded simultaneously and a specific script on the cloud.ubertone.eu allows synchronizing data from the carriage file with the UB-Lab P data. We also adapted our interface detection to obtain a robust and accurate measurement of the riverbed position. As for some discharge conditions, the signal was weaker, scatterers settling faster, another routine was to measure in fixed positions of the transect. Another script developed by Ubertone on the cloud then averages the data collected in each fixed position for a better spatial cover. In both scripts, the velocity data beyond the detected interface are kept out and the data are filtered with the Doppler signal-to-noise ratio measured by the UB-Lab P. U/W are processed from the monostatic velocities and the Doppler angles given by the user. Other entry parameters allow to take into account environment aspects such as model scale. This new compact and autonomous device makes the installation and integration of a UVP in lab setups easier, leading to more application possibilities. The UB-Lab P is a new powerful tool for measuring the velocity field in physical models for hydraulic research and engineering.