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Ulrich Lemmin

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Related publications (67)

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

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

A multi-frequency Acoustic Concentration and Velocity Profiler (ACVP) for boundary layer measurements of fine-scale flow and sediment transport processes

Ulrich Lemmin, David Hurther

The use of acoustics to measure sediment transport boundary layer processes has gained increasing acceptance over the past two decades. This has occurred through the development of increasingly sophisticated measuring systems and theoretical developments, ...

2011

Evolution of superficial lake water temperature profile under diurnal radiative forcing

Ulrich Lemmin, Nikki Vercauteren, Marc Parlange, Wolf Hendrik Huwald, Ivan Lunati

In lentic water bodies, such as lakes, the water temperature near the surface typically increases during the day, and decreases during the night as a consequence of the diurnal radiative forcing (solar and infrared radiation). These temperature variations ...

American Geophysical Union2011

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

Velocity and Turbulence Distribution in Unsteady Rough-Bed Open-Channel Flow

Ulrich Lemmin, Fereshteh Bagherimiyab Hunkeler

2009

A Study of Bottom Boundary Layer Dynamics in Unsteady Sediment-Laden Open-Channel Flow Using Acoustic Profiling

Ulrich Lemmin, David Hurther, Fereshteh Bagherimiyab Hunkeler

2009

Experimental study on fine sediment resuspension in accelerating rough-bed open-channel flow

Ulrich Lemmin, Fereshteh Bagherimiyab Hunkeler

CRC Press2009

Subgrid-Scale Dynamics of Water Vapour, Heat, and Momentum over a Lake

Ulrich Lemmin, Nikki Vercauteren, Marc Parlange, Wolf Hendrik Huwald, Charles Vivant Ignacio Meneveau

We examine the dynamics of turbulence subgrid (or sub-filter) scales over a lake surface and the implications for large-eddy simulations (LES) of the atmospheric boundary layer. The analysis is based on measurements obtained during the Lake-Atmosphere Turb ...

2008

Parameterization of the logarithmic layer of double-averaged streamwise velocity profiles in gravel-bed river flows

Ulrich Lemmin, Mário Jorge Rodrigues Pereira Da Franca

The logarithmic layer of double-averaged (in time and space) streamwise velocity profiles obtained from field measurements made in the Swiss rivers, Venoge and Chamberonne is parameterized and discussed. Velocity measurements were made using a 3D Acoustic ...

2008

Improved Turbulence Profiling with Field-Adapted Acoustic Doppler Velocimeters Using a Bifrequency Doppler Noise Suppression Method

Ulrich Lemmin, David Hurther

A novel noise reduction method and corresponding technique are presented for improving turbulence measurements with acoustic Doppler velocimeters (ADVs) commonly used in field studies of coastal and nearshore regions, rivers, lakes, and estuaries. This bif ...

2008

Near-field flow structure of a confined wall jet on flat and concave rough walls

Ulrich Lemmin, Ismail Albayrak

Experimental results are presented of the mean flow and turbulence characteristics in the near field of a plane wall jet issuing from a nozzle onto flat and concave walls consisting of fixed sand beds. This is a flow configuration of interest for sediment ...

Cambridge University Press2008

Turbulent transport in the outer region of rough-wall open-channel flows: the contribution of large coherent shear stress structures (LC3S)

Ulrich Lemmin, David Hurther

Cambridge University Press2007

Discussion of « Turbulence Measurements with Acoustic Doppler Velocimeters. » by Carlos M. García, Mariano I. Cantero, Yarko Niño, and Marcelo H. García

Ulrich Lemmin, David Hurther

2007

Discussion of « Unobstructed and obstructed turbulent flows in gravel bed rivers » by H. M. Tritico and R.H Hotchkiss

Ulrich Lemmin, Mário Jorge Rodrigues Pereira Da Franca

2007

Dynamics of secoundary of secondary currents and surface boils in turbulent open-channel flow revealed by surface particle image velocity measurements

Ulrich Lemmin, Ismail Albayrak

IAHR2007

Moyens de réduction de bruit des mesures acoustiques de la turbulence - Means of noise reduction in acoustic turbulence measurements

Ulrich Lemmin, Koen Blanckaert

2006

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Ulrich Lemmin

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

A multi-frequency Acoustic Concentration and Velocity Profiler (ACVP) for boundary layer measurements of fine-scale flow and sediment transport processes

Evolution of superficial lake water temperature profile under diurnal radiative forcing

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

Velocity and Turbulence Distribution in Unsteady Rough-Bed Open-Channel Flow

A Study of Bottom Boundary Layer Dynamics in Unsteady Sediment-Laden Open-Channel Flow Using Acoustic Profiling

Experimental study on fine sediment resuspension in accelerating rough-bed open-channel flow

Subgrid-Scale Dynamics of Water Vapour, Heat, and Momentum over a Lake

Parameterization of the logarithmic layer of double-averaged streamwise velocity profiles in gravel-bed river flows

Improved Turbulence Profiling with Field-Adapted Acoustic Doppler Velocimeters Using a Bifrequency Doppler Noise Suppression Method

Near-field flow structure of a confined wall jet on flat and concave rough walls

Turbulent transport in the outer region of rough-wall open-channel flows: the contribution of large coherent shear stress structures (LC3S)

Discussion of « Turbulence Measurements with Acoustic Doppler Velocimeters. » by Carlos M. García, Mariano I. Cantero, Yarko Niño, and Marcelo H. García

Discussion of « Unobstructed and obstructed turbulent flows in gravel bed rivers » by H. M. Tritico and R.H Hotchkiss

Dynamics of secoundary of secondary currents and surface boils in turbulent open-channel flow revealed by surface particle image velocity measurements

Moyens de réduction de bruit des mesures acoustiques de la turbulence - Means of noise reduction in acoustic turbulence measurements

Eliminating velocity aliasing in acoustic Doppler velocity profiler data

Detection and reconstruction of coherent structures based on wavelet multiresolution analysis

Cold-water events and dissipation in the mixed layer of a lake

Turbulence measurements in shallow flows in gravel-bed rivers