TY  - CHAP
A1  - Oertel, Mario
A1  - Bung, Daniel B.
A1  - Schlenkhoff, Andreas
ED  - Carstensen, Dirk
T1  - Blocksteinrampen in Riegelbauweise : Neue Bemessungsansätze
T2  - Staubauwerke : planen, bauen, betreiben; 35. Dresdner Wasserbaukolloquium 2012, 08. - 09. März 2012
Y1  - 2012
SN  - 978-3-86780-261-1
SP  - 317
EP  - 326
PB  - Selbstverl. der Techn. Univ.
CY  - Dresden
ER  - 
TY  - JOUR
A1  - Bung, Daniel B.
T1  - Non-intrusive detection of air–water surface roughness in self-aerated chute flows
JF  - Journal of hydraulic research
Y1  - 2013
SN  - 1814-2079 (E-Journal); 0022-1686 (Print)
VL  - Vol. 51
IS  - Iss. 3
SP  - 322
EP  - 329
PB  - Taylor & Francis
CY  - London
ER  - 
TY  - CHAP
A1  - Bung, Daniel B.
A1  - Pagliara, S.
T1  - Proceedings of the International Workshop on Hydraulic Design of Low-Head Structures : Aachen, Germany, February, 20-22, 2013 /  D. Bung ; S. Pagliara (eds.)
Y1  - 2013
SN  - 978-3-939230-04-5
PB  - Bundesanst. für Wasserbau
CY  - Karlsruhe
ER  - 
TY  - JOUR
A1  - Oertel, Mario
A1  - Bung, Daniel B.
T1  - Initial stage of two-dimensional dam-break waves: laboratory versus VOF
JF  - Journal of hydraulic research
N2  - Since several decades, dam-break waves have been of main research interest. Mathematical approaches have been developed by analytical, physical and numerical models within the past 120 years. During the past 10 years, the number of research investigations has increased due to improved measurement techniques as well as significantly increased computer memories and performances. In this context, the present research deals with the initial stage of two-dimensional dam-break waves by comparing physical and numerical model results as well as analytical approaches. High-speed images and resulting particle image velocimetry calculations are thereby compared with the numerical volume-of-fluid (VOF) method, included in the commercial code FLOW-3D. Wave profiles and drag forces on placed obstacles are analysed in detail. Generally, a good agreement between the laboratory and VOF results is found.
KW  - VOF
KW  - PIV
KW  - physical model
KW  - numerical model
KW  - drag force
KW  - dam-break
Y1  - 2012
U6  - http://dx.doi.org/10.1080/00221686.2011.639981
SN  - 1814-2079 (E-Journal); 0022-1686 (Print)
VL  - 50
IS  - 1
SP  - 89
EP  - 97
PB  - Taylor & Francis
CY  - London
ER  - 
TY  - JOUR
A1  - Bung, Daniel B.
T1  - Developing flow in skimming flow regime on embankment stepped spillways
JF  - Journal of hydraulic research
Y1  - 2011
SN  - 1814-2079 (E-Journal); 0022-1686 (Print)
VL  - Vol. 49
IS  - Iss. 5
SP  - 639
EP  - 648
PB  - Taylor & Francis
CY  - London
ER  - 
TY  - CHAP
A1  - Bung, Daniel B.
T1  - Non-intrusive measuring of air-water flow properties in self-aerated stepped spillway flow
T2  - Balance and uncertainty - water in a changing world :  proceedings of the 34th IAHR world congress ; 33rd Hydrology and Water Resources Symposium ; 10th Conference on Hydraulics in Water Engineering ; 26 June - 1 July 2011, Brisbane, Australia
Y1  - 2011
SN  - 978-0-85825-868-6
SP  - 2380
EP  - 2387
ER  - 
TY  - CHAP
A1  - Ahmed, H.
A1  - Schlenkhoff, A.
A1  - Bung, Daniel B.
T1  - Hydrodynamic characteristics of vertical slotted wall breakwaters
T2  - Balance and uncertainty - water in a changing world :  proceedings of the 34th IAHR world congress ; 33rd Hydrology and Water Resources Symposium ; 10th Conference on Hydraulics in Water Engineering ; 26 June - 1 July 2011, Brisbane, Australia
Y1  - 2011
SN  - 978-0-85825-868-6
SP  - 1179
EP  - 1186
ER  - 
TY  - JOUR
A1  - Bung, Daniel B.
T1  - Fließcharakteristik und Sauerstoffeintrag bei selbstbelüfteten Gerinneströmungen auf Kaskaden mit gemäßigter Neigung
JF  - Österreichische Wasser- und Abfallwirtschaft
Y1  - 2011
SN  - 1613-7566 (E-Journal); 0945-358X (Print)
VL  - Vol. 63
IS  - Iss. 3-4
SP  - 76
EP  - 81
PB  - Springer
CY  - Berlin
ER  - 
TY  - CHAP
A1  - Kerpen, N.
A1  - Verworn, F.
A1  - Bung, Daniel B.
A1  - Daemrich, K.-F.
A1  - Schlurmann, Torsten
T1  - Ermittlung von Wellenüberlaufmengen an Sturmflutschutzwänden auf Deichen
T2  - Maritimer Wasserbau und Küsteningenieurwesen : 8. FZK-Kolloquium : Hannover 10. März, 2011
Y1  - 2011
SN  - 1610-5249
SP  - 63
EP  - 68
ER  - 
TY  - CHAP
A1  - Bung, Daniel B.
A1  - Oertel, M.
A1  - Schlenkhoff, A.
A1  - Schlurmann, Torsten
ED  - Obrusnik, Ivan
T1  - Flash flood awareness and prevention in Germany
T2  - Early warning for flash floods : international workshop, Praha 2011 : workshop proceedings
Y1  - 2010
SN  - 978-80-86690-91-9
SP  - 34
EP  - 40
ER  - 
TY  - CHAP
A1  - Heinz, G.
A1  - Oertel, Mario
A1  - Bung, Daniel B.
ED  - Janssen, Robert
T1  - Investigations on a cooling water system for a gas tubine facility concerning air vortexes and sediment transport
T2  - Hydraulic structures: useful water harvesting systems or relics? : Third International Junior Researcher and Engineer Workshop on Hydraulic Structures (IJREWHS'10) : Edinburgh, Scotland, U.K., 2-3 May 2010
Y1  - 2010
SN  - 9781742720159
SP  - 109
EP  - 116
PB  - School of Civil Engineering, The University of Queensland
CY  - Brisbane
ER  - 
TY  - CHAP
A1  - Bung, Daniel B.
ED  - Theobald, S.
T1  - Optimierung des potentiellen Sauerstoffeintrags auf Treppenschussrinnen mit gemäßigter Neigung
T2  - 9. JuWi-Treffen : Beiträge zum Treffen junger Wissenschaftlerinnen und junger Wissenschaftler deutschsprachiger Wasserbauinstitute
Y1  - 2009
SP  - 73
EP  - 78
PB  - Universität Kassel
CY  - Kassel
ER  - 
TY  - CHAP
A1  - Kerpen, N. B.
A1  - Bung, Daniel B.
A1  - Schlurmann, Torsten
ED  - Janssen, Robert
T1  - Physical model investigations of ships passing through a lock
T2  - Hydraulic structures: useful water harvesting systems or relics? : Third International Junior Researcher and Engineer Workshop on Hydraulic Structures (IJREWHS'10) : Edinburgh, Scotland, U.K., 2-3 May 2010
Y1  - 2010
SN  - 9781742720159
SP  - 93
EP  - 100
PB  - School of Civil Engineeering, The University of Queensland
CY  - Brisbane
ER  - 
TY  - CHAP
A1  - Bung, Daniel B.
A1  - Schlenkhoff, Andreas
T1  - Self-aerated skimming flow on embankment stepped spillways : the effect of additional micro-roughness on energy dissipation and oxygen transfer
T2  - Proceedings from first IAHR European congress : May 2010, Edinburgh
Y1  - 2010
SN  - 9780956595102
SP  - Artikelkennnummer HSIIId
PB  - Heriot-Watt University, School of the Built Environment
CY  - Edinburgh
ER  - 
TY  - CHAP
A1  - Kerpen, N. B.
A1  - Bung, Daniel B.
A1  - Schlurmann, Torsten
T1  - Physical model investigations of pressure distributions next to ships passing through a lock
T2  - 5th Chinese-German Joint Symposium on Hydraulic and Ocean Engineering : CG JOINT 2010
Y1  - 2010
SN  - 978-7-5618-3671-2
SP  - 514
EP  - 519
PB  - Univ. Press
CY  - Tianjin
ER  - 
TY  - CHAP
A1  - Bung, Daniel B.
T1  - A comparative study of self-aerated stepped spillway and smooth invert chute flow: the effect of step-induced macro roughness
T2  - 5th Chinese-German Joint Symposium on Hydraulic and Ocean Engineering : CG JOINT 2010
Y1  - 2010
SN  - 978-7-5618-3671-2
SP  - 451
EP  - 456
PB  - Univ. Press
CY  - Tianjin
ER  - 
TY  - CHAP
A1  - Bung, Daniel B.
A1  - Sun, Q.
A1  - Meireles, I.
A1  - Matos, J.
A1  - Viseu, T.
T1  - USBR type III stilling basin performance for steep stepped spillways
T2  - Hydraulic structures into the 21st century : 4th IAHR International Symposium on Hydraulic Structures : 9.-11.2.2012, Porto
Y1  - 2012
SN  - 978-989-8509-01-7
ER  - 
TY  - CHAP
A1  - Oertel, Mario
A1  - Bung, Daniel B.
T1  - Characteristics of cross-bar block ramp flows
T2  - Hydraulic structures into the 21st century : 4th IAHR International Symposium on Hydraulic Structures : 9.-11.2.2012, Porto
Y1  - 2012
SN  - 978-989-8509-01-7
ER  - 
TY  - CHAP
A1  - Bung, Daniel B.
T1  - Sensitivity of phase detection techniques in aerated chute flows to hydraulic design parameters
T2  - 2nd European IAHR congress : 27. - 29. June 2012, München
Y1  - 2012
SN  - 978-3-943683-03-5
SP  - Artikelkennnummer: B15
PB  - Lehrstuhl u. Versuchsanst. für Wasserbau u. Wasserwirtschaft d. TU München
CY  - München
ER  - 
TY  - CHAP
A1  - Schlurmann, Torsten
A1  - Bung, Daniel B.
T1  - Experimental investigation of flow-induced radial gate vibrations at Lower Subansiri dam
T2  - Sixth Chinese-German Joint Symposium on Hydraulic and Ocean Engineering : JOINT 2012 : 23.-29.9.2012, Keelung
Y1  - 2012
SP  - 7
EP  - 14
ER  - 
TY  - CHAP
A1  - Oertel, Mario
A1  - Bung, Daniel B.
T1  - Comparison of 2D dam-break waves with VOF and SPH method
T2  - Proceedings of the 35th IAHR world congress : 8.-13.9.2013, Chengdu, China
Y1  - 2013
SP  - Artikelkennnummer: A11113
PB  - Tsinghua Univ. Press
CY  - Beijing
ER  - 
TY  - CHAP
A1  - Bung, Daniel B.
T1  - Air-water surface roughness in self-aerated stepped spillway flows
T2  - 35th IAHR world congress : 8.-13.9.2013, Chengdu, China
Y1  - 2013
SP  - Artikelkennnummer: A11045
PB  - Tsinghua Univ. Press
CY  - Beijing
ER  - 
TY  - CHAP
A1  - Gogolin, C.
A1  - Carvalho, R.
A1  - Bung, Daniel B.
A1  - Matos, J.
T1  - Experimental and numerical investigation of steady and unsteady flows in roughened channels with cross beams
T2  - 35th IAHR world congress : 8.-13.9.2013, Chengdu, China
Y1  - 2013
SP  - Artikelkennnummer: A10837C
PB  - Tsinghua Univ. Press
CY  - Beijing
ER  - 
TY  - CHAP
A1  - Bung, Daniel B.
A1  - Schlenkhoff, Andreas
T1  - Selbstbelüftete Gerinneströmungen auf Treppenschussrinnen
T2  - Talsperren im Wandel : 15. Deutsches Talsperrensymposium ; Beiträge zur Tagung am 14. bis 16. April 2010 im Eurogress Aachen
Y1  - 2010
SN  - 978-3-8322-9043-6
SP  - 39
EP  - 47
ER  - 
TY  - THES
A1  - Bung, Daniel B.
T1  - Zur selbstbelüfteten Gerinneströmung auf Kaskaden mit gemäßigter Neigung. (Bericht / Fachbereich Bautechnik, Lehr- und Forschungsgebiet Wasserbau und Wasserwirtschaft, Bergische Universität Gesamthochschule Wuppertal ; Bd. 16)
Y1  - 2009
SN  - 978-3-8322-8382-7
N1  - Zugl.: Wuppertal, Univ., Diss., 2009
PB  - Shaker
CY  - Aachen
ER  - 
TY  - CHAP
A1  - Bung, Daniel B.
A1  - Schlenkhoff, Andreas
A1  - Oertel, M.
T1  - Self-aerated skimming flow on embankment stepped spillways
T2  - Water engineering for sustainable environment : 33rd IAHR congress ; 9 - 14 August 2009, Vancouver, British Columbia, Canada
Y1  - 2009
SN  - 9789078046080
SP  - 1 CD-ROM
ER  - 
TY  - CHAP
A1  - Oertel, M.
A1  - Bung, Daniel B.
A1  - Schlenkhoff, Andreas
T1  - Flash flood awareness and prevention
T2  - Water engineering for sustainable environment : 33rd IAHR congress ; 9 - 14 August 2009, Vancouver, British Columbia, Canada
Y1  - 2009
SN  - 9789078046080
SP  - 1 CD-ROM
ER  - 
TY  - CHAP
A1  - Schlenkhoff, Andreas
A1  - Bung, Daniel B.
T1  - Prediction of oxygen transfer in self-aerated skimming flow on embankment stepped spillways
T2  - Water engineering for sustainable environment : 33rd IAHR congress ; 9 - 14 August 2009, Vancouver, British Columbia, Canada
Y1  - 2009
SN  - 9789078046080
SP  - 1 CD-ROM
ER  - 
TY  - CHAP
A1  - Bung, Daniel B.
A1  - Hildebrandt, Arndt
A1  - Oertel, Mario
A1  - Schlenkhoff, Andreas
A1  - Schlurmann, Torsten
ED  - McKee Smith, Jane
T1  - Bore propagation over a submerged horizontal plate by physical and numerical simulation
T2  - Coastal engineering 2008 : proceedings of the 31st international conference; Hamburg, Germany, 31 August - 5 September 2008 ; Vol. 4
Y1  - 2008
SN  - 9814277401 ; 9789814277402
SP  - 3542
EP  - 3553
ER  - 
TY  - CHAP
A1  - Bung, Daniel B.
A1  - Schlenkhoff, Andreas
ED  - Pagliara, Stefano
T1  - Optimization of the reaeration potential on embankment stepped spillways in skimming flow regime
T2  - Hydraulic structures : proceedings of the second International Junior Researcher and Engineer Workshop on Hydraulic Structures, Pisa, Italy, 30 July-1 August 2008
Y1  - 2008
SN  - 978-88-8492-568-8
SP  - 97
EP  - 106
ER  - 
TY  - CHAP
A1  - Oertel, Mario
A1  - Bung, Daniel B.
A1  - Schlenkhoff, Andreas
T1  - Flächenhafte Flutwellenausbreitung und anschließende Flutung unterirdischer Bauwerke
T2  - Fünf Jahre nach der Flut : Hochwasserschutzkonzepte - Planung, Berechnung, Realisierung = Five years after the flood : concepts of flood protection - design, evaluation, realisation ; Dresdner Wasserbaukolloquium 2007, 08. - 09. Oktober 2007 /  [Hrsg. von H.-B. Horlacher ...] (Dresdner Wasserbauliche Mitteilungen ; H. 35)
Y1  - 2007
SN  - 978-3-86005-571-7
SP  - 475
EP  - 484
PB  - Techn. Univ.
CY  - Dresden
ER  - 
TY  - JOUR
A1  - Leandro, J.
A1  - Bung, Daniel B.
A1  - Carvalho, R.
T1  - Measuring void fraction and velocity fields of a stepped spillway for skimming flow using non-intrusive methods
JF  - Experiments in fluids
Y1  - 2014
U6  - http://dx.doi.org/10.1007/s00348-014-1732-6
SN  - 0723-4864 (Print) ; 1432-1114 (Online)
IS  - 55
SP  - Art. 1732
PB  - Springer Nature
CY  - Heidelberg
ER  - 
TY  - CHAP
A1  - Bung, Daniel B.
A1  - Oertel, Mario
T1  - Manipulation of non-aerated cavity flow on a stepped spillway model
T2  - 3rd European IAHR Congress : April 14 – 16, 2014, Porto
Y1  - 2014
PB  - Univ. of Porto
CY  - Porto
ER  - 
TY  - CHAP
A1  - Oertel, Mario
A1  - Bung, Daniel B.
T1  - Numerische Strömungssimulation von Fließgewässern - Wo stehen wir und was werden wir im Laufe der nächsten Jahre erreichen?
T2  - Simulationsverfahren und Modelle für Wasserbau und Wasserwirtschaft = Simulation techniques and models for hydraulic engineering and water management / 37. Dresdner Wasserbaukolloquium 2014, 13. - 14. März 2014. (Dresdner wasserbauliche Mitteilungen ; H. 50)
Y1  - 2014
SN  - 978-3-86780-349-6
SP  - 19
EP  - 30
ER  - 
TY  - CHAP
A1  - Bung, Daniel B.
T1  - Observations on non-aerated flow and air entrainment on moderately sloped stepped spillways
T2  - 7th Chinese-German Joint Symposium on Hydraulic and Ocean Engineering : 8. - 12. Sept. 2014, Hannover
Y1  - 2014
N1  - Kennwortgeschützter Zugang. Passwort bei Prof. Bung, Fachbereich Bauingenieurwesen
SP  - 1
EP  - 8
ER  - 
TY  - CHAP
A1  - Chanson, Hubert
A1  - Bung, Daniel B.
A1  - Matos, J.
T1  - Stepped spillways and cascades
T2  - Energy dissipation in hydraulic structures / Hubert Chanson (ed.)
Y1  - 2015
SN  - 978-1-138-02755-8 (print) ; 978-1-315-68029-3 (e-Book)
SP  - 45
EP  - 64
PB  - CRC Press
CY  - Boca Raton, Fla. [u.a.]
ER  - 
TY  - CHAP
A1  - Bung, Daniel B.
ED  - Rowinski, Pawel
T1  - Laboratory models of free-surface flows
T2  - Rivers - physical, fluvial and environmental processes
N2  - Hydraulic modeling is the classical approach to investigate and describe complex fluid motion. Many empirical formulas in the literature used for the hydraulic design of river training measures and structures have been developed using experimental data from the laboratory. Although computer capacities have increased to a high level which allows to run complex numerical simulations on standard workstation nowadays, non-standard design of structures may still raise the need to perform physical model investigations. These investigations deliver insight into details of flow patterns and the effect of varying boundary conditions. Data from hydraulic model tests may be used for calibration of numerical models as well. As the field of hydraulic modeling is very complex, this chapter intends to give a short overview on capacities and limits of hydraulic modeling in regard to river flows and hydraulic structures only. The reader shall get a first idea of modeling principles and basic considerations. More detailed information can be found in the references.
KW  - Physical modeling
KW  - Similitude
KW  - Open channels
KW  - Hydraulic structures
Y1  - 2015
SN  - 978-3-319-17718-2 ; 978-3-319-17719-9
U6  - http://dx.doi.org/10.1007/978-3-319-17719-9_9
SP  - 213
EP  - 228
PB  - Springer
CY  - Cham
ER  - 
TY  - CHAP
A1  - Valero, Daniel
A1  - Bung, Daniel B.
T1  - Hybrid investigation of air transport processes in moderately sloped stepped spillway flows
T2  - E-proceedings of the 36th IAHR World Congress 28 June – 3 July, 2015, The Hague, the Netherlands
Y1  - 2015
SP  - 1
EP  - 10
ER  - 
TY  - CHAP
A1  - Oertel, Mario
A1  - Balmes, Jan P.
A1  - Bung, Daniel B.
T1  - Numerical simulation of erosion processes on crossbar block ramps
T2  - E-proceedings of the 36th IAHR World Congress 28 June – 3 July, 2015, The Hague, the Netherlands
Y1  - 2015
SP  - 1
EP  - 8
ER  - 
TY  - CHAP
A1  - Bung, Daniel B.
A1  - Valero, Daniel
T1  - Image processing for bubble image velocimetry in self-aerated flows
T2  - E-proceedings of the 36th IAHR World Congress 28 June – 3 July, 2015, The Hague, the Netherlands
Y1  - 2015
SP  - 1
EP  - 8
ER  - 
TY  - JOUR
A1  - Oertel, Mario
A1  - Bung, Daniel B.
T1  - Numerische Strömungssimulationen von Fließgewässern : Praxisanwendungen und zukünftige Entwicklungen
JF  - Korrespondenz Wasserwirtschaft : KW
Y1  - 2015
SN  - 1616-430X
VL  - 8
IS  - H. 3
SP  - 177
EP  - 182
PB  - Gesellschaft zur Förderung der Abwassertechnik
CY  - Hennef
ER  - 
TY  - CHAP
A1  - Bühler, P.
A1  - Leandro, J.
A1  - Bung, Daniel B.
A1  - Lopes, P.
A1  - Carvalho, R.
T1  - Measuring void fraction of a stepped spillway with non-intrusive methods using different image resolutions
T2  - 2nd International Workshop on Hydraulic Structures : Data Validation : Coimbra, Portugal, 8-9 May 2015
Y1  - 2015
SP  - 1
EP  - 8
ER  - 
TY  - CHAP
A1  - Lopes, Pedro
A1  - Bung, Daniel B.
A1  - Leandro, Jorge
A1  - Carvalho, Rita F.
T1  - The effect of cross-waves in physical stepped spillway models
T2  - E-proceedings of the 36th IAHR World Congress ; 28 June - 3 July, 2015, The Hague, the Netherlands
Y1  - 2015
SP  - 1
EP  - 9
ER  - 
TY  - CHAP
A1  - Valero, Daniel
A1  - Bung, Daniel B.
A1  - Crookston, B. M.
A1  - Matos, J.
ED  - Crookston, B.
ED  - Tullis, B.
T1  - Numerical investigation of USBR type III stilling basin performance downstream of smooth and stepped spillways
BT  - Session 1: Hydraulic structures
T2  - Hydraulic Structures and Water System Management. 6th IAHR International Symposium on Hydraulic Structures, Portland, OR, 27-30 June 2016
Y1  - 2016
SN  - 978-1-884575-75-4
U6  - http://dx.doi.org/10.15142/T340628160853
SP  - 635
EP  - 646
ER  - 
TY  - CHAP
A1  - Bung, Daniel B.
A1  - Valero, Daniel
ED  - Crookston, B.
ED  - Tullis, B.
T1  - Application of the optical flow method to velocity determination in hydraulic structure models
BT  - Session 11: Fish passage and shiplocks
T2  - Hydraulic Structures and Water System Management. 6th IAHR International Symposium on Hydraulic Structures, Portland, OR, 27-30 June 2016
Y1  - 2016
SN  - 978-1-884575-75-4
U6  - http://dx.doi.org/10.15142/T3150628160853
SP  - 223
EP  - 232
ER  - 
TY  - CHAP
A1  - Oertel, M.
A1  - Bung, Daniel B.
ED  - Crookston, B.
ED  - Tullis, B.
T1  - Scouring processes downstream a crossbar block ramp
BT  - Session 3: Scour, erosion, sedimentation
T2  - Hydraulic Structures and Water System Management. 6th IAHR International Symposium on Hydraulic Structures, Portland, OR, 27-30 June 2016
Y1  - 2016
SN  - 978-1-884575-75-4
U6  - http://dx.doi.org/10.15142/T3340628160853
SP  - 549
EP  - 559
ER  - 
TY  - JOUR
A1  - Lopes, Pedro
A1  - Leandro, Jorge
A1  - Carvalho, Rita F.
A1  - Bung, Daniel B.
T1  - Alternating skimming flow over a stepped spillway
JF  - Environmental Fluid Mechanics
Y1  - 2017
U6  - http://dx.doi.org/10.1007/s10652-016-9484-x
SN  - 1573-1510
VL  - 17
IS  - 2
SP  - 303
EP  - 322
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Valero, Daniel
A1  - Bung, Daniel B.
T1  - Sensitivity of turbulent Schmidt number and turbulence model to simulations of jets in crossflow
JF  - Environmental Modelling and Software
N2  - Environmental discharges have been traditionally designed by means of cost-intensive and time-consuming experimental studies. Some extensively validated models based on an integral approach have been often employed for water quality problems, as recommended by USEPA (i.e.: CORMIX). In this study, FLOW-3D is employed for a full 3D RANS modelling of two turbulent jet-to-crossflow cases, including free surface jet impingement. Results are compared to both physical modelling and CORMIX to better assess model performance. Turbulence measurements have been collected for a better understanding of turbulent diffusion's parameter sensitivity. Although both studied models are generally able to reproduce jet trajectory, jet separation downstream of the impingement has been reproduced only by RANS modelling. Additionally, concentrations are better reproduced by FLOW-3D when the proper turbulent Schmidt number is used. This study provides a recommendation on the selection of the turbulence model and the turbulent Schmidt number for future outfall structures design studies.
Y1  - 2016
U6  - http://dx.doi.org/10.1016/j.envsoft.2016.04.030
SN  - 1364-8152 (electronic)
VL  - 82
SP  - 218
EP  - 228
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Valero, Daniel
A1  - Bung, Daniel B.
T1  - Development of the interfacial air layer in the non-aerated region of high-velocity spillway flows: Instabilities growth, entrapped air and influence on the self-aeration onset
JF  - International Journal of Multiphase Flow
N2  - Self-aeration is traditionally explained by the water turbulent boundary layer outer edge intersection with the free surface. This paper presents a discussion on the commonly accepted hypothesis behind the computation of the critical point of self-aeration in spillway flows and a new formulation is proposed based on the existence of a developing air flow over the free surface. Upstream of the inception point of self-aeration, some surface roughening has been often reported in previous studies which consequently implies some entrapped air transport and air–water flows coupling. Such air flow is proven in this study by presenting measured air velocities and computing the air boundary layer thickness for a 1V:2H smooth chute flow. Additionally, the growth rate of free surface waves has been analysed by means of Ultrasonic Sensors measurements, obtaining also the entrapped air concentration. High-speed camera imaging has been used for qualitative study of the flow perturbations.
Y1  - 2016
U6  - http://dx.doi.org/10.1016/j.ijmultiphaseflow.2016.04.012
SN  - 0301-9322
VL  - 84
SP  - 66
EP  - 74
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - CHAP
A1  - Kerpen, Nils B.
A1  - Bung, Daniel B.
A1  - Valero, Daniel
A1  - Schlurmann, Torsten
T1  - Energy dissipation within the wave run-up at stepped revetments
T2  - 8th Chinese-German Joint Symposium on Hydraulic and Ocean Engineering, Qingdao, China
KW  - energy disspation
KW  - wave run-up
KW  - friction
Y1  - 2016
ER  - 
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  - 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  - CHAP
A1  - Valero, Daniel
A1  - Bung, Daniel B.
A1  - Oertel, M.
ED  - Dewals, Benjamin
T1  - Turbulent dispersion in bounded horizontal jets : RANS capabilities and physical modeling comparison
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/b21902-13
SP  - 49
EP  - 55
PB  - CRC Press
ER  - 
TY  - CHAP
A1  - Valero, Daniel
A1  - Bung, Daniel B.
T1  - Interfacial velocity estimation in highly aerated stepped spillway flows with a single tip fibre optical probe and Artificial Neural Networks
T2  - 6th IAHR International Junior Researcher and Engineer Workshop on Hydraulic Structures, May 30th to June 1st 2016. Lübeck, Germany
N2  - Air-water flows can be found in different engineering applications: from nuclear engineering to huge hydraulic structures. In this paper, a single tip fibre optical probe has been used to record high frequency (over 1 MHz) phase functions at different locations of a stepped spillway. These phase functions have been related to the interfacial velocities by means of Artificial Neural Networks (ANN) and the measurements of a classical double tip conductivity probe. Special attention has been put to the input selection and the ANN dimensions. Finally, ANN have shown to be able to link the signal rising times and plateau shapes to the air-water interfacial velocity.
Y1  - 2016
U6  - http://dx.doi.org/10.15142/T3Q590
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  - Valero, Daniel
A1  - Bung, Daniel B.
T1  - Reformulating self-aeration in hydraulic structures: Turbulent growth of free surface perturbations leading to air entrainment
JF  - International Journal of Multiphase Flow
N2  - A new formulation for the prediction of free surface dynamics related to the turbulence occurring nearby is proposed. This formulation, altogether with a breakup criterion, can be used to compute the inception of self-aeration in high velocity flows like those occurring in hydraulic structures. Assuming a simple perturbation geometry, a kinematic and a non-linear momentum-based dynamic equation are formulated and forces acting on a control volume are approximated. Limiting steepness is proposed as an adequate breakup criterion. Role of the velocity fluctuations normal to the free surface is shown to be the main turbulence quantity related to self-aeration and the role of the scales contained in the turbulence spectrum are depicted. Surface tension force is integrated accounting for large displacements by using differential geometry for the curvature estimation. Gravity and pressure effects are also contemplated in the proposed formulation. The obtained equations can be numerically integrated for each wavelength, hence resulting in different growth rates and allowing computation of the free surface roughness wavelength distribution. Application to a prototype scale spillway (at the Aviemore dam) revealed that most unstable wavelength was close to the Taylor lengthscale. Amplitude distributions have been also obtained observing different scaling for perturbations stabilized by gravity or surface tension. The proposed theoretical framework represents a new conceptualization of self-aeration which explains the characteristic rough surface at the non-aerated region as well as other previous experimental observations which remained unresolved for several decades.
Y1  - 2018
U6  - http://dx.doi.org/10.1016/j.ijmultiphaseflow.2017.12.011
SN  - 0301-9322
VL  - 100
SP  - 127
EP  - 142
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Valero, Daniel
A1  - Bung, Daniel B.
T1  - Artificial Neural Networks and pattern recognition for air-water flow velocity estimation using a single-tip optical fibre probe
JF  - Journal of Hydro-environment Research
Y1  - 2017
U6  - http://dx.doi.org/10.1016/j.jher.2017.08.004
SN  - 1570-6443
VL  - 19
IS  - 3
SP  - 150
EP  - 159
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Kerpen, Nils B.
A1  - Bung, Daniel B.
A1  - Valero, Daniel
A1  - Schlurmann, Torsten
T1  - Energy dissipation within the wave run-up at stepped revetments
JF  - Journal of Ocean University of China
Y1  - 2017
U6  - http://dx.doi.org/10.1007/s11802-017-3355-z
SN  - 1993-5021
VL  - 16
IS  - 4
SP  - 649
EP  - 654
PB  - Springer
CY  - Berlin
ER  - 
TY  - CHAP
A1  - Valero, Daniel
A1  - Bung, Daniel B.
A1  - Erpicum, Sebastien
A1  - Dewals, Benjamin
T1  - Numerical study of turbulent oscillations around a cylinder: RANS capabilities and sensitivity analysis
T2  - Proceedings of the 37th IAHR World Congress August 13 – 18, 2017, Kuala Lumpur, Malaysia
Y1  - 2017
SN  - 2521-716X
SP  - 3126
EP  - 3135
ER  - 
TY  - CHAP
A1  - Bung, Daniel B.
A1  - Valero, Daniel
T1  - FlowCV - An open-source toolbox for computer vision applications in turbulent flows
T2  - Proceedings of the 37th IAHR World Congress August 13 – 18, 2017, Kuala Lumpur, Malaysia
Y1  - 2017
SN  - 2521-716X
SP  - 5356
EP  - 5365
ER  - 
TY  - JOUR
A1  - Valero, Daniel
A1  - Bung, Daniel B.
T1  - Vectrino profiler spatial filtering for shear flows based on the mean velocity gradient equation
JF  - Journal of Hydraulic Engineering
N2  - A new methodology is proposed to spatially filter acoustic Doppler velocimetry data from a Vectrino profiler based on the differential mean velocity equation. Lower and upper bounds are formulated in terms of physically based flow constraints. Practical implementation is discussed, and its application is tested against data gathered from an open-channel flow over a stepped macroroughness surface. The method has proven to detect outliers occurring all over the distance range sampled by the Vectrino profiler and has shown to remain applicable out of the region of validity of the velocity gradient equation. Finally, a statistical analysis suggests that physically obtained bounds are asymptotically representative.
Y1  - 2018
U6  - http://dx.doi.org/10.1061/(ASCE)HY.1943-7900.0001485
SN  - 0733-9429
N1  - Article number 04018037
VL  - 144
IS  - 7
PB  - ASCE
CY  - Reston, Va.
ER  - 
TY  - JOUR
A1  - Valero, Daniel
A1  - Bung, Daniel B.
A1  - Crookston, B.M.
T1  - Energy dissipation of a Type III basin under design and adverse conditions for stepped and smooth spillways
JF  - Journal of Hydraulic Engineering
N2  - New information regarding the influence of a stepped chute on the hydraulic performance of the United States Bureau of Reclamation (Reclamation) Type III hydraulic jump stilling basin is presented for design (steady) and adverse (decreasing tailwater) conditions. Using published experimental data and computational fluid dynamics (CFD) models, this paper presents a detailed comparison between smooth-chute and stepped-chute configurations for chute slopes of 0.8H:1V and 4H:1V and Froude numbers (F) ranging from 3.1 to 9.5 for a Type III basin designed for F = 8. For both stepped and smooth chutes, the relative role of each basin element was quantified, up to the most hydraulic extreme case of jump sweep-out. It was found that, relative to a smooth chute, the turbulence generated by a stepped chute causes a higher maximum velocity decay within the stilling basin, which represents an enhancement of the Type III basin’s performance but also a change in the relative role of the basin elements. Results provide insight into the ability of the CFD models [unsteady Reynolds-averaged Navier-Stokes (RANS) equations with renormalization group (RNG) k-ϵ turbulence model and volume-of-fluid (VOF) for free surface tracking] to predict the transient basin flow structure and velocity profiles. Type III basins can perform adequately with a stepped chute despite the effects steps have on the relative role of each basin element. It is concluded that the classic Type III basin design, based upon methodology by reclamation specific to smooth chutes, can be hydraulically improved for the case of stepped chutes for design and adverse flow conditions using the information presented herein.
Y1  - 2018
U6  - http://dx.doi.org/10.1061/(ASCE)HY.1943-7900.0001482
SN  - 0733-9429
N1  - Article number 04018036
VL  - 144
IS  - 7
PB  - ASCE
CY  - Reston, Va.
ER  - 
TY  - JOUR
A1  - Zhang, G.
A1  - Valero, Daniel
A1  - Bung, Daniel B.
A1  - Chanson, H.
T1  - On the estimation of free-surface turbulence using ultrasonic sensors
JF  - Flow Measurement and Instrumentation
N2  - Accurate determination of free-surface dynamics has attracted much research attention during the past decade and has important applications in many environmental and water related areas. In this study, the free-surface dynamics in several turbulent flows commonly found in nature were investigated using a synchronised setup consisting of an ultrasonic sensor and a high-speed video camera. Basic sensor capabilities were examined in dry conditions to allow for a better characterisation of the present sensor model. The ultrasonic sensor was found to adequately reproduce free-surface dynamics up to the second order, especially in two-dimensional scenarios with the most energetic modes in the low frequency range. The sensor frequency response was satisfactory in the sub-20 Hz band, and its signal quality may be further improved by low-pass filtering prior to digitisation. The application of the USS to characterise entrapped air in high-velocity flows is also discussed.
Y1  - 2018
U6  - http://dx.doi.org/10.1016/j.flowmeasinst.2018.02.009
SN  - 0955-5986
VL  - 60
SP  - 171
EP  - 184
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Bung, Daniel B.
A1  - Valero, Daniel
T1  - Re-aeration on stepped spillways with special consideration of entrained and entrapped air
JF  - Geosciences
N2  - As with most high-velocity free-surface flows, stepped spillway flows become self-aerated when the drop height exceeds a critical value. Due to the step-induced macro-roughness, the flow field becomes more turbulent than on a similar smooth-invert chute. For this reason, cascades are oftentimes used as re-aeration structures in wastewater treatment. However, for stepped spillways as flood release structures downstream of deoxygenated reservoirs, gas transfer is also of crucial significance to meet ecological requirements. Prediction of mass transfer velocities becomes challenging, as the flow regime differs from typical previously studied flow conditions. In this paper, detailed air-water flow measurements are conducted on stepped spillway models with different geometry, with the aim to estimate the specific air-water interface. Re-aeration performances are determined by applying the absorption method. In contrast to earlier studies, the aerated water body is considered a continuous mixture up to a level where 75% air concentration is reached. Above this level, a homogenous surface wave field is considered, which is found to significantly affect the total air-water interface available for mass transfer. Geometrical characteristics of these surface waves are obtained from high-speed camera investigations. The results show that both the mean air concentration and the mean flow velocity have influence on the mass transfer. Finally, an empirical relationship for the mass transfer on stepped spillway models is proposed.
Y1  - 2018
SN  - 2076-3263
VL  - 8
IS  - 9
SP  - Article number 333
PB  - MDPI
CY  - Basel
ER  - 
TY  - CHAP
A1  - Bung, Daniel B.
A1  - Valero, Daniel
A1  - Hermens, G.
T1  - Hybrid investigation on the hydraulic performance of a new trapezoidal fishway
T2  - 7th IAHR International Symposium on Hydraulic Structures, ISHS 2018
Y1  - 2018
SN  - 978-069213277-7
U6  - http://dx.doi.org/10.15142/T3S06R
SP  - 184
EP  - 193
ER  - 
TY  - CHAP
A1  - Bung, Daniel B.
A1  - Tullis, Blake
T1  - Hydraulic Structures - ISHS2018 in Perspective
T2  - 7th IAHR International Symposium on Hydraulic Structures, Aachen, Germany, 15-18 May
Y1  - 2018
SN  - 978-0-692-13277-7
U6  - http://dx.doi.org/10.15142/T3WH2B
ER  - 
TY  - CHAP
A1  - Valero, Daniel
A1  - Vogel, Jochen
A1  - Schmidt, Daniel
A1  - Bung, Daniel B.
T1  - Three-dimensional flow structure inside the cavity of a non-aerated stepped chute
T2  - 7th IAHR International Symposium on Hydraulic Structures, Aachen, Germany, 15-18 May
Y1  - 2018
SN  - 978-0-692-13277-7
U6  - http://dx.doi.org/10.15142/T3GH17
ER  - 
TY  - JOUR
A1  - Kramer, Matthias
A1  - Valero, Daniel
A1  - Chanson, Hubert
A1  - Bung, Daniel B.
T1  - Towards reliable turbulence estimations with phase-detection probes: an adaptive window cross-correlation technique
JF  - Experiments in Fluids
Y1  - 2019
U6  - http://dx.doi.org/10.1007/s00348-018-2650-9
SN  - 1432-1114
VL  - 60
EP  - Article number 2
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Valero, Daniel
A1  - Chanson, Hubert
A1  - Bung, Daniel B.
T1  - Robust estimators for turbulence properties assessment
Y1  - 2019
SP  - 1
EP  - 24
ER  - 
TY  - CHAP
A1  - Kerpen, Nils B.
A1  - Schoonees, Talia
A1  - Schlurmann, Torsten
A1  - Valero, Daniel
A1  - Bung, Daniel B.
T1  - waveSTEPS – Wellenauf- und Wellenüberlauf an getreppten Deckwerken
T2  - 24. KFKI-Seminar 2019, 21.11.2019
Y1  - 2019
ER  - 
TY  - JOUR
A1  - Valero, Daniel
A1  - Chanson, Hubert
A1  - Bung, Daniel B.
T1  - Robust estimators for free surface turbulence characterization: A stepped spillway application
JF  - Flow Measurement and Instrumentation
N2  - Robust estimators are parameters insensitive to the presence of outliers. However, they presume the shape of the variables’ probability density function. This study exemplifies the sensitivity of turbulent quantities to the use of classic and robust estimators and the presence of outliers in turbulent flow depth time series. A wide range of turbulence quantities was analysed based upon a stepped spillway case study, using flow depths sampled with Acoustic Displacement Meters as the flow variable of interest. The studied parameters include: the expected free surface level, the expected fluctuation intensity, the depth skewness, the autocorrelation timescales, the vertical velocity fluctuation intensity, the perturbations celerity and the one-dimensional free surface turbulence spectrum. Three levels of filtering were utilised prior to applying classic and robust estimators, showing that comparable robustness can be obtained either using classic estimators together with an intermediate filtering technique or using robust estimators instead, without any filtering technique.
Y1  - 2020
U6  - http://dx.doi.org/10.1016/j.flowmeasinst.2020.101809
SN  - 0955-5986
VL  - 76
IS  - Art. 101809
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Valero, D.
A1  - Bung, Daniel B.
A1  - Crookston, B. M.
T1  - Closure to “Energy Dissipation of a Type III Basin under Design and Adverse Conditions for Stepped and Smooth Spillways”
JF  - Journal of Hydraulic Engineering
Y1  - 2019
U6  - http://dx.doi.org/10.1061/(ASCE)HY.1943-7900.0001669
VL  - 146
IS  - 2
PB  - ASCE
CY  - Reston, Va.
ER  - 
TY  - CHAP
A1  - Valero, Daniel
A1  - Kramer, Matthias
A1  - Bung, Daniel B.
A1  - Chanson, Hubert
T1  - A stochastic bubble generator for air-water flow research
T2  - E-proceedings of the 38th IAHR World Congress, September 1-6, 2019, Panama City, Panama
Y1  - 2019
U6  - http://dx.doi.org/10.3850/38WC092019-0909
SP  - 5714
EP  - 5721
ER  - 
TY  - CHAP
A1  - Tullis, Blake P.
A1  - Crookston, Brian M.
A1  - Bung, Daniel B.
T1  - Weir head-discharge relationships: A multi-lab exercise
T2  - E-proceedings of the 38th IAHR World Congress  September 1-6, 2019, Panama City, Panama
Y1  - 2019
SP  - 1
EP  - 15
ER  - 
TY  - CHAP
A1  - Bung, Daniel B.
A1  - Oertel, Mario
T1  - Wave breaking over a submerged horizontal plate: Optical Flow, LES and RANS
T2  - E-proceedings of the 38th IAHR World Congress  September 1-6, 2019, Panama City, Panama
Y1  - 2019
U6  - http://dx.doi.org/10.3850/38WC092019-0509
SP  - 3690
EP  - 3698
ER  - 
TY  - JOUR
A1  - Bung, Daniel B.
A1  - Crookston, Brian M.
A1  - Valero, Daniel
T1  - Turbulent free-surface monitoring with an RGB-D sensor: the hydraulic jump case
JF  - Journal of Hydraulic Research
Y1  - 2020
U6  - http://dx.doi.org/10.1080/00221686.2020.1844810
SN  - 1814-2079
PB  - Taylor & Francis
CY  - London
ER  - 
TY  - JOUR
A1  - Erpicum, Sebastien
A1  - Crookston, Brian M.
A1  - Bombardelli, Fabian
A1  - Bung, Daniel B.
A1  - Felder, Stefan
A1  - Mulligan, Sean
A1  - Oertel, Mario
A1  - Palermo, Michele
T1  - Hydraulic structures engineering: An evolving science in a changing world
JF  - Wires Water
Y1  - 2021
U6  - http://dx.doi.org/10.1002/wat2.1505
SN  - 2049-1948
VL  - 8
IS  - 2
PB  - Wiley
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Valero, Daniel
A1  - Schalko, Isabella
A1  - Friedrich, Heide
A1  - Abad, Jorge D.
A1  - Bung, Daniel B.
A1  - Donchyts, Gennadii
A1  - Felder, Stefan
A1  - Ferreira, Rui M. L.
A1  - Hohermuth, Benjamin
A1  - Kramer, Matthias
A1  - Li, Danxun
A1  - Mendes, Luis
A1  - Moreno-Rodenas, Antonio
A1  - Nones, Michael
A1  - Paron, Paolo
A1  - Ruiz-Villanueva, Virginia
A1  - Wang, Ruo-Qian
A1  - Franca, Mario J.
T1  - Pathways towards democratization of hydro-environment observations and data
JF  - Iahr White Paper Series
Y1  - 2021
IS  - 1
SP  - 1
EP  - 9
PB  - International Association for Hydro-Environment Engineering and Research (IAHR)
ER  - 
TY  - JOUR
A1  - Valero, Daniel
A1  - Bung, Daniel B.
A1  - Erpicum, Sebastien
A1  - Peltier, Yann
A1  - Dewals, Benjamin
T1  - Unsteady shallow meandering flows in rectangular reservoirs: a modal analysis of URANS modelling
JF  - Journal of Hydro-environment Research
N2  - Shallow flows are common in natural and human-made environments. Even for simple rectangular shallow reservoirs, recent laboratory experiments show that the developing flow fields are particularly complex, involving large-scale turbulent structures. For specific combinations of reservoir size and hydraulic conditions, a meandering jet can be observed. While some aspects of this pseudo-2D flow pattern can be reproduced using a 2D numerical model, new 3D simulations, based on the unsteady Reynolds-Averaged Navier-Stokes equations, show consistent advantages as presented herein. A Proper Orthogonal Decomposition was used to characterize the four most energetic modes of the meandering jet at the free surface level, allowing comparison against experimental data and 2D (depth-averaged) numerical results. Three different isotropic eddy viscosity models (RNG k-ε, k-ε, k-ω) were tested. The 3D models accurately predicted the frequency of the modes, whereas the amplitudes of the modes and associated energy were damped for the friction-dominant cases and augmented for non-frictional ones. The performance of the three turbulence models remained essentially similar, with slightly better predictions by RNG k-ε model in the case with the highest Reynolds number. Finally, the Q-criterion was used to identify vortices and study their dynamics, assisting on the identification of the differences between: i) the three-dimensional phenomenon (here reproduced), ii) its two-dimensional footprint in the free surface (experimental observations) and iii) the depth-averaged case (represented by 2D models).
KW  - coherent structures
KW  - hydraulic modelling
KW  - model performance
KW  - Proper Orthogonal Decomposition
KW  - Q-criterion
Y1  - 2022
U6  - http://dx.doi.org/10.1016/j.jher.2022.03.002
SN  - 1570-6443
IS  - In Press
PB  - Elsevier
CY  - Amsterdam
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  - JOUR
A1  - Oertel, Mario
A1  - Bung, Daniel B.
T1  - Stability and scour development of bed material on crossbar block ramps
JF  - International journal of sediment research
N2  - Block ramps are ecologically oriented drop structures with adequate energy dissipation and partially moderate flow velocities. A special case is given with crossbar block ramps, where the upstream and downstream level difference is reduced by a series of basins. To prevent the total structure from failing, the stability of single boulders within the crossbars and the bed material in between must be guaranteed. The present paper addresses the stability of bed material and scour development for various flow regimes. Any bed material erosion may affect the stability of the crossbar boulders, which in turn can result in major damages of the ramp. Therefore new design approaches are developed to choose an appropriate bed material size and to avoid failures of crossbar block ramp structures.
Y1  - 2015
U6  - http://dx.doi.org/10.1016/j.ijsrc.2014.12.003
SN  - 1001-6279
VL  - 30
IS  - 4
SP  - 344
EP  - 350
PB  - Elsevier
CY  - Amsterdam
ER  -