Publications related to Acoustic Doppler current profiler

Large-scale coherent flow structures in rough-bed open-channel flow observed in fluctuations of three-dimensional velocity, skin friction and bed pressure

Ulrich Lemmin, Fereshteh Bagherimiyab Hunkeler

The dynamics of large-scale coherent structures (LSCS) are investigated in a rough-bed flow over the whole water column and longitudinal and transverse turbulent fluxes of momentum are compared. The relation between LSCS and fluctuations of skin friction a ...

Taylor & Francis Ltd2018

Coreless Open-Loop Current Transducers Based On Hall Effect Sensor Csa-1V

Radivoje Popovic

The paper provides an overview of coreless open-loop current transducers based on Hall effect sensor CSA-1V. Depending on the implementation method and current range, the presented transducers are divided in the four groups. The transducers are capable to ...

Univ Nis2016

Hydroacoustic Modeling of a Cavitation Vortex Rope for a Francis Turbine

Christian Landry

Hydraulic machines subject to off-design operation involve the presence of cavitating flow regimes in the draft tube. The cavitation vortex rope at part load conditions is described as an excitation source for the hydraulic system, and interactions between ...

EPFL2015

Detection and reconstruction of large-scale coherent flow structures in gravel-bed rivers

Ulrich Lemmin, Mário Jorge Rodrigues Pereira Da Franca

Large-scale flow structures (LSFS) in the streamwise direction are important features of gravel-bed river flows, because they may contribute to sediment transport and gas exchange. In the present study, these structures are detected using Huang's empirical ...

Wiley-Blackwell2015

Shear velocity estimates in rough-bed open-channel flow

Ulrich Lemmin, Fereshteh Bagherimiyab Hunkeler

Shear velocity u(*) is an important parameter in geophysical flows, in particular with respect to sediment transport dynamics. In this study, we investigate the feasibility of applying five standard methods [the logarithmic mean velocity profile, the Reyno ...

Wiley-Blackwell2013

Sediment Suspension Dynamics in Turbulent Unsteady, Depth-Varying Open-Channel Flow over a Gravel Bed

Fereshteh Bagherimiyab Hunkeler

Even though flow in natural rivers and channels is generally unsteady, only a few studies on turbulent structures in unsteady open-channel flows have been carried out. In hydraulic engineering problems, unsteady flow is often approximated with concepts of ...

EPFL2012

Secondary Currents and Corresponding Surface Velocity Patterns in a Turbulent Open-Channel Flow over a Rough Bed

Ulrich Lemmin, Ismail Albayrak

River and open-channel flows present complex three-dimensional (3D) structures in the water column and on the surface as a result of the existence of secondary currents driven by either centrifugal force or turbulence. This paper experimentally investigate ...

2011

Improving the accuracy of four-receiver acoustic Doppler velocimeter (ADV) measurements in turbulent boundary layer flows

Ulrich Lemmin, Fereshteh Bagherimiyab Hunkeler

Acoustic Doppler instrument measurements suffer from random spikes and Doppler noise. Using a four-receiver ADV (acoustic Doppler velocimeter; Vectrino manufactured by Nortek) that allows recording beam velocities, we combine a spike-removal procedure on t ...

Association for the Sciences of Limnology and Oceanography (ASLO)2010

Improvement of Acoustic Doppler Velocimetry in steady and unsteady turbulent open-channel flows by means of seeding with hydrogen bubbles

Anton Schleiss, Giovanni De Cesare, Koen Blanckaert, Tobias Meile

Velocimetry is used in various fields of research. In hydraulics, Ultrasonic Velocimetry based on the Doppler Shift effect can accurately resolve the quasi-instantaneous flow field [Takeda Y. Velocity profile measurement by Ultrasonic Doppler method. Exper ...

Elsevier2008