Measuring flow velocity in a large-scale wave flume
What happens when a wave passes by? How can the flowfield be characterized when there are waves superimposed on a turbulent bottom boundary layer? A grid of Vectrinos and other Nortek equipment helped researchers using the CIEM large-scale wave flume in Barcelona to find the answers.
A combination of down- and side-looking Vectrinos were installed at different heights above a sandy bed in the CIEM flume, at heights 0.09 m, 0.21 m, 0.35 m, 0.64 m, 1 m, 1.4 m, 1.6 m and 1.7 m. A 2 MHz Aquadopp Profiler with right-angle head and high-resolution firmware was placed at the bottom of the flume and in the center of the flow.
Obtaining flow velocity in a large-scale wave regime
The aim of the experiment was to obtain data about flow velocity in a large-scale wave regime, where the bottom boundary layer flow is turbulent. An additional objective was to verify that Nortek’s HR Aquapro, sampling at 8 Hz, could be used to study the steady stream under different wave conditions. The information obtained by the array of Nortek Acoustic Doppler Velocimeters (ADVs) and the information gathered with the Aquapro was compared to verify the HR profiler performance. The instrumentation setup shown in the image was established as part of the Hydralab III Access experiment (http://hydralab.eu) headed by Dr. Pietro Scandura (University of Catania, Italy). The purpose of the experiment was to investigate the effect of wave asymmetry generating steady flows over a sandy bottom which, in turn, leads to ripple formation. Several combinations of sinusoidal and cnoidal waves were investigated.