@article{BungValero2018,
  author    = {Bung, Daniel B. and Valero, Daniel},
  title     = {Re-aeration on stepped spillways with special consideration of entrained and entrapped air},
  series = {Geosciences},
  volume    = {8},
  journal   = {Geosciences},
  number    = {9},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2076-3263},
  pages     = {Article number 333},
  year      = {2018},
  abstract  = {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.},
  language  = {en}
}
@inproceedings{BungValeroHermens2018,
  author    = {Bung, Daniel B. and Valero, Daniel and Hermens, G.},
  title     = {Hybrid investigation on the hydraulic performance of a new trapezoidal fishway},
  series = {7th IAHR International Symposium on Hydraulic Structures, ISHS 2018},
  booktitle = {7th IAHR International Symposium on Hydraulic Structures, ISHS 2018},
  isbn      = {978-069213277-7},
  doi       = {10.15142/T3S06R},
  pages     = {184 -- 193},
  year      = {2018},
  language  = {de}
}
@article{KramerValeroChansonetal.2019,
  author    = {Kramer, Matthias and Valero, Daniel and Chanson, Hubert and Bung, Daniel B.},
  title     = {Towards reliable turbulence estimations with phase-detection probes: an adaptive window cross-correlation technique},
  series = {Experiments in Fluids},
  volume    = {60},
  journal   = {Experiments in Fluids},
  publisher = {Springer},
  address   = {Berlin},
  issn      = {1432-1114},
  doi       = {10.1007/s00348-018-2650-9},
  year      = {2019},
  language  = {en}
}
@article{ValeroChansonBung2019,
  author    = {Valero, Daniel and Chanson, Hubert and Bung, Daniel B.},
  title     = {Robust estimators for turbulence properties assessment},
  pages     = {1 -- 24},
  year      = {2019},
  language  = {en}
}
@article{ValeroChansonBung2020,
  author    = {Valero, Daniel and Chanson, Hubert and Bung, Daniel B.},
  title     = {Robust estimators for free surface turbulence characterization: A stepped spillway application},
  series = {Flow Measurement and Instrumentation},
  volume    = {76},
  journal   = {Flow Measurement and Instrumentation},
  number    = {Art. 101809},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0955-5986},
  doi       = {10.1016/j.flowmeasinst.2020.101809},
  year      = {2020},
  abstract  = {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.},
  language  = {en}
}
@inproceedings{ValeroKramerBungetal.2019,
  author    = {Valero, Daniel and Kramer, Matthias and Bung, Daniel B. and Chanson, Hubert},
  title     = {A stochastic bubble generator for air-water flow research},
  series = {E-proceedings of the 38th IAHR World Congress, September 1-6, 2019, Panama City, Panama},
  booktitle = {E-proceedings of the 38th IAHR World Congress, September 1-6, 2019, Panama City, Panama},
  doi       = {10.3850/38WC092019-0909},
  pages     = {5714 -- 5721},
  year      = {2019},
  language  = {en}
}
@article{BungCrookstonValero2020,
  author    = {Bung, Daniel B. and Crookston, Brian M. and Valero, Daniel},
  title     = {Turbulent free-surface monitoring with an RGB-D sensor: the hydraulic jump case},
  series = {Journal of Hydraulic Research},
  journal   = {Journal of Hydraulic Research},
  publisher = {Taylor \& Francis},
  address   = {London},
  issn      = {1814-2079},
  doi       = {10.1080/00221686.2020.1844810},
  year      = {2020},
  language  = {en}
}
@article{ValeroSchalkoFriedrichetal.2021,
  author    = {Valero, Daniel and Schalko, Isabella and Friedrich, Heide and Abad, Jorge D. and Bung, Daniel B. and Donchyts, Gennadii and Felder, Stefan and Ferreira, Rui M. L. and Hohermuth, Benjamin and Kramer, Matthias and Li, Danxun and Mendes, Luis and Moreno-Rodenas, Antonio and Nones, Michael and Paron, Paolo and Ruiz-Villanueva, Virginia and Wang, Ruo-Qian and Franca, Mario J.},
  title     = {Pathways towards democratization of hydro-environment observations and data},
  series = {Iahr White Paper Series},
  journal   = {Iahr White Paper Series},
  number    = {1},
  publisher = {International Association for Hydro-Environment Engineering and Research (IAHR)},
  pages     = {1 -- 9},
  year      = {2021},
  language  = {en}
}
@article{ValeroBungErpicumetal.2022,
  author    = {Valero, Daniel and Bung, Daniel B. and Erpicum, Sebastien and Peltier, Yann and Dewals, Benjamin},
  title     = {Unsteady shallow meandering flows in rectangular reservoirs: a modal analysis of URANS modelling},
  series = {Journal of Hydro-environment Research},
  journal   = {Journal of Hydro-environment Research},
  number    = {In Press},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1570-6443},
  doi       = {10.1016/j.jher.2022.03.002},
  year      = {2022},
  abstract  = {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).},
  language  = {en}
}
@article{BungValero2016,
  author    = {Bung, Daniel B. and Valero, Daniel},
  title     = {Optical flow estimation in aerated flows},
  series = {Journal of Hydraulic Research},
  volume    = {54},
  journal   = {Journal of Hydraulic Research},
  number    = {5},
  publisher = {Taylor \& Francis},
  address   = {London},
  doi       = {10.1080/00221686.2016.1173600},
  pages     = {575 -- 580},
  year      = {2016},
  abstract  = {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.},
  language  = {en}
}
@inproceedings{KerpenBungSchlurmann2010,
  author    = {Kerpen, N. B. and Bung, Daniel B. and Schlurmann, Torsten},
  title     = {Physical model investigations of ships passing through a lock},
  series = {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},
  booktitle = {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},
  editor    = {Janssen, Robert},
  publisher = {School of Civil Engineeering, The University of Queensland},
  address   = {Brisbane},
  organization    = {International Junior Researcher and Engineer Workshop on Hydraulic Structures <3, 2010, Edinburgh>},
  isbn      = {9781742720159},
  pages     = {93 -- 100},
  year      = {2010},
  language  = {en}
}
@inproceedings{KerpenBungSchlurmann2010,
  author    = {Kerpen, N. B. and Bung, Daniel B. and Schlurmann, Torsten},
  title     = {Physical model investigations of pressure distributions next to ships passing through a lock},
  series = {5th Chinese-German Joint Symposium on Hydraulic and Ocean Engineering : CG JOINT 2010},
  booktitle = {5th Chinese-German Joint Symposium on Hydraulic and Ocean Engineering : CG JOINT 2010},
  publisher = {Univ. Press},
  address   = {Tianjin},
  organization    = {Chinese-German Joint Symposium on Hydraulic and Ocean Engineering <5, 2010, Tianjin>},
  isbn      = {978-7-5618-3671-2},
  pages     = {514 -- 519},
  year      = {2010},
  language  = {en}
}
@book{BleningerBrendaBungetal.2016,
  author    = {Bleninger, T. and Brenda, M. and Bung, Daniel B. and Hengl, M. and Schmid, B.H. and Schneider, E. and Sonnenburg, A. and Stoschek, O.},
  title     = {DWA-Regelwerk M 544-1 : Merkblatt: Ausbreitungsprobleme von Einleitungen - Prozesse, Methoden und Modelle - Teil 1: Anwendungsgrundlagen, Sch{\"a}tzformeln und eindimensionale Modelle},
  address   = {Hennef},
  organization    = {DWA, Deutsche Vereinigung f{\"u}r Wasserwirtschaft, Abwasser und Abfall e.V.},
  isbn      = {978-3-88721-280-3},
  pages     = {59 Seiten},
  year      = {2016},
  language  = {de}
}
@book{BleningerBrendaBungetal.2016,
  author    = {Bleninger, T. and Brenda, M. and Bung, Daniel B. and Hengl, M. and Schmid, B.H. and Schneider, E. and Sonnenburg, A. and Stoschek, O.},
  title     = {DWA-Regelwerk M 544-2 : Merkblatt: Ausbreitungsprobleme von Einleitungen - Prozesse, Methoden und Modelle - Teil 2: Mehrdimensionale Modelle},
  address   = {Hennef},
  organization    = {DWA, Deutsche Vereinigung f{\"u}r Wasserwirtschaft, Abwasser und Abfall e.V.},
  isbn      = {978-3-88721-281-0},
  pages     = {91 Seiten},
  year      = {2016},
  language  = {de}
}
@article{ValeroBungCrookston2019,
  author    = {Valero, D. and Bung, Daniel B. and Crookston, B. M.},
  title     = {Closure to "Energy Dissipation of a Type III Basin under Design and Adverse Conditions for Stepped and Smooth Spillways"},
  series = {Journal of Hydraulic Engineering},
  volume    = {146},
  journal   = {Journal of Hydraulic Engineering},
  number    = {2},
  publisher = {ASCE},
  address   = {Reston, Va.},
  doi       = {10.1061/(ASCE)HY.1943-7900.0001669},
  year      = {2019},
  language  = {en}
}
@inproceedings{OertelBungSchlenkhoff2012,
  author    = {Oertel, Mario and Bung, Daniel B. and Schlenkhoff, Andreas},
  title     = {Blocksteinrampen in Riegelbauweise : Neue Bemessungsans{\"a}tze},
  series = {Staubauwerke : planen, bauen, betreiben; 35. Dresdner Wasserbaukolloquium 2012, 08. - 09. M{\"a}rz 2012},
  booktitle = {Staubauwerke : planen, bauen, betreiben; 35. Dresdner Wasserbaukolloquium 2012, 08. - 09. M{\"a}rz 2012},
  editor    = {Carstensen, Dirk},
  publisher = {Selbstverl. der Techn. Univ.},
  address   = {Dresden},
  organization    = {Technische Universit{\"a}t Dresden, Fakult{\"a}t Bauingenieurwesen},
  isbn      = {978-3-86780-261-1},
  pages     = {317 -- 326},
  year      = {2012},
  language  = {de}
}
@article{Bung2013,
  author    = {Bung, Daniel B.},
  title     = {Non-intrusive detection of air-water surface roughness in self-aerated chute flows},
  series = {Journal of hydraulic research},
  volume    = {Vol. 51},
  journal   = {Journal of hydraulic research},
  number    = {Iss. 3},
  publisher = {Taylor \& Francis},
  address   = {London},
  issn      = {1814-2079 (E-Journal); 0022-1686 (Print)},
  pages     = {322 -- 329},
  year      = {2013},
  language  = {en}
}
@inproceedings{BungPagliara2013,
  author    = {Bung, Daniel B. and Pagliara, S.},
  title     = {Proceedings of the International Workshop on Hydraulic Design of Low-Head Structures : Aachen, Germany, February, 20-22, 2013 / D. Bung ; S. Pagliara (eds.)},
  publisher = {Bundesanst. f{\"u}r Wasserbau},
  address   = {Karlsruhe},
  isbn      = {978-3-939230-04-5},
  pages     = {X, 230 S. + 1 CD-ROM},
  year      = {2013},
  language  = {en}
}
@article{OertelBung2012,
  author    = {Oertel, Mario and Bung, Daniel B.},
  title     = {Initial stage of two-dimensional dam-break waves: laboratory versus VOF},
  series = {Journal of hydraulic research},
  volume    = {50},
  journal   = {Journal of hydraulic research},
  number    = {1},
  publisher = {Taylor \& Francis},
  address   = {London},
  issn      = {1814-2079 (E-Journal); 0022-1686 (Print)},
  doi       = {10.1080/00221686.2011.639981},
  pages     = {89 -- 97},
  year      = {2012},
  abstract  = {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.},
  language  = {en}
}
@article{Bung2011,
  author    = {Bung, Daniel B.},
  title     = {Developing flow in skimming flow regime on embankment stepped spillways},
  series = {Journal of hydraulic research},
  volume    = {Vol. 49},
  journal   = {Journal of hydraulic research},
  number    = {Iss. 5},
  publisher = {Taylor \& Francis},
  address   = {London},
  issn      = {1814-2079 (E-Journal); 0022-1686 (Print)},
  pages     = {639 -- 648},
  year      = {2011},
  language  = {en}
}