TY  - CHAP
A1  - Bung, Daniel B.
A1  - Valero, Daniel
ED  - Dewals, Benjamin
T1  - Image processing techniques for velocity estimation in highly aerated flows: bubble image velocimetry vs. optical flow
T2  - Sustainable Hydraulics in the Era of Global Change : Proceedings of the 4th IAHR Europe Congress (Liege, Belgium, 27-29 July 2016)
Y1  - 2016
SN  - 978-1-138-02977-4
SN  - 978-1-4987-8149-7 (eBook)
U6  - http://dx.doi.org/10.1201/b21902-31
SP  - 151
EP  - 157
PB  - CRC Press
ER  - 
TY  - JOUR
A1  - Bung, Daniel B.
A1  - Valero, Daniel
T1  - Optical flow estimation in aerated flows
JF  - Journal of Hydraulic Research
N2  - Optical flow estimation is known from Computer Vision where it is used to determine obstacle movements through a sequence of images following an assumption of brightness conservation. This paper presents the first study on application of the optical flow method to aerated stepped spillway flows. For this purpose, the flow is captured with a high-speed camera and illuminated with a synchronized LED light source. The flow velocities, obtained using a basic Horn–Schunck method for estimation of the optical flow coupled with an image pyramid multi-resolution approach for image filtering, compare well with data from intrusive conductivity probe measurements. Application of the Horn–Schunck method yields densely populated flow field data sets with velocity information for every pixel. It is found that the image pyramid approach has the most significant effect on the accuracy compared to other image processing techniques. However, the final results show some dependency on the pixel intensity distribution, with better accuracy found for grey values between 100 and 150.
Y1  - 2016
U6  - http://dx.doi.org/10.1080/00221686.2016.1173600
VL  - 54
IS  - 5
SP  - 575
EP  - 580
PB  - Taylor & Francis
CY  - London
ER  - 
TY  - BOOK
A1  - Bleninger, T.
A1  - Brenda, M.
A1  - Bung, Daniel B.
A1  - Hengl, M.
A1  - Schmid, B.H.
A1  - Schneider, E.
A1  - Sonnenburg, A.
A1  - Stoschek, O.
T1  - DWA-Regelwerk M 544-1 : Merkblatt: Ausbreitungsprobleme von Einleitungen - Prozesse, Methoden und Modelle - Teil 1: Anwendungsgrundlagen, Schätzformeln und eindimensionale Modelle
Y1  - 2016
SN  - 978-3-88721-280-3
CY  - Hennef
ER  - 
TY  - BOOK
A1  - Bleninger, T.
A1  - Brenda, M.
A1  - Bung, Daniel B.
A1  - Hengl, M.
A1  - Schmid, B.H.
A1  - Schneider, E.
A1  - Sonnenburg, A.
A1  - Stoschek, O.
T1  - DWA-Regelwerk M 544-2 : Merkblatt: Ausbreitungsprobleme von Einleitungen - Prozesse, Methoden und Modelle - Teil 2: Mehrdimensionale Modelle
Y1  - 2016
SN  - 978-3-88721-281-0
CY  - Hennef
ER  - 
TY  - JOUR
A1  - Bayon, Arnau
A1  - Valero, Daniel
A1  - Garcia-Bartual, Rafael
A1  - Vallés-Morán, Francisco José
A1  - López-Jiménez, P. Amparo
T1  - Performance assessment of OpenFOAM and FLOW-3D in the numerical modeling of a low Reynolds number hydraulic jump
JF  - Environmental Modelling & Software
N2  - A comparative performance analysis of the CFD platforms OpenFOAM and FLOW-3D is presented, focusing on a 3D swirling turbulent flow: a steady hydraulic jump at low Reynolds number. Turbulence is treated using RANS approach RNG k-ε. A Volume Of Fluid (VOF) method is used to track the air–water interface, consequently aeration is modeled using an Eulerian–Eulerian approach. Structured meshes of cubic elements are used to discretize the channel geometry. The numerical model accuracy is assessed comparing representative hydraulic jump variables (sequent depth ratio, roller length, mean velocity profiles, velocity decay or free surface profile) to experimental data. The model results are also compared to previous studies to broaden the result validation. Both codes reproduced the phenomenon under study concurring with experimental data, although special care must be taken when swirling flows occur. Both models can be used to reproduce the hydraulic performance of energy dissipation structures at low Reynolds numbers.
Y1  - 2016
SN  - 1364-8152
U6  - http://dx.doi.org/10.1016/j.envsoft.2016.02.018
VL  - 80
SP  - 322
EP  - 335
PB  - Elsevier
CY  - Amsterdam
ER  -