@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}
}
@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}
}
@article{Bung2011,
  author    = {Bung, Daniel B.},
  title     = {Fließcharakteristik und Sauerstoffeintrag bei selbstbel{\"u}fteten Gerinnestr{\"o}mungen auf Kaskaden mit gem{\"a}ßigter Neigung},
  series = {{\"O}sterreichische Wasser- und Abfallwirtschaft},
  volume    = {Vol. 63},
  journal   = {{\"O}sterreichische Wasser- und Abfallwirtschaft},
  number    = {Iss. 3-4},
  publisher = {Springer},
  address   = {Berlin},
  issn      = {1613-7566 (E-Journal); 0945-358X (Print)},
  pages     = {76 -- 81},
  year      = {2011},
  language  = {de}
}
@article{LeandroBungCarvalho2014,
  author    = {Leandro, J. and Bung, Daniel B. and Carvalho, R.},
  title     = {Measuring void fraction and velocity fields of a stepped spillway for skimming flow using non-intrusive methods},
  series = {Experiments in fluids},
  journal   = {Experiments in fluids},
  number    = {55},
  publisher = {Springer Nature},
  address   = {Heidelberg},
  issn      = {0723-4864 (Print) ; 1432-1114 (Online)},
  doi       = {10.1007/s00348-014-1732-6},
  pages     = {Art. 1732},
  year      = {2014},
  language  = {en}
}
@article{OertelBung2015,
  author    = {Oertel, Mario and Bung, Daniel B.},
  title     = {Numerische Str{\"o}mungssimulationen von Fließgew{\"a}ssern : Praxisanwendungen und zuk{\"u}nftige Entwicklungen},
  series = {Korrespondenz Wasserwirtschaft : KW},
  volume    = {8},
  journal   = {Korrespondenz Wasserwirtschaft : KW},
  number    = {H. 3},
  publisher = {Gesellschaft zur F{\"o}rderung der Abwassertechnik},
  address   = {Hennef},
  issn      = {1616-430X},
  pages     = {177 -- 182},
  year      = {2015},
  language  = {de}
}
@article{LopesLeandroCarvalhoetal.2017,
  author    = {Lopes, Pedro and Leandro, Jorge and Carvalho, Rita F. and Bung, Daniel B.},
  title     = {Alternating skimming flow over a stepped spillway},
  series = {Environmental Fluid Mechanics},
  volume    = {17},
  journal   = {Environmental Fluid Mechanics},
  number    = {2},
  publisher = {Springer},
  address   = {Berlin},
  issn      = {1573-1510},
  doi       = {10.1007/s10652-016-9484-x},
  pages     = {303 -- 322},
  year      = {2017},
  language  = {en}
}
@article{ValeroBung2016,
  author    = {Valero, Daniel and Bung, Daniel B.},
  title     = {Sensitivity of turbulent Schmidt number and turbulence model to simulations of jets in crossflow},
  series = {Environmental Modelling and Software},
  volume    = {82},
  journal   = {Environmental Modelling and Software},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1364-8152 (electronic)},
  doi       = {10.1016/j.envsoft.2016.04.030},
  pages     = {218 -- 228},
  year      = {2016},
  abstract  = {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.},
  language  = {en}
}
@article{ValeroBung2016,
  author    = {Valero, Daniel and Bung, Daniel B.},
  title     = {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},
  series = {International Journal of Multiphase Flow},
  volume    = {84},
  journal   = {International Journal of Multiphase Flow},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0301-9322},
  doi       = {10.1016/j.ijmultiphaseflow.2016.04.012},
  pages     = {66 -- 74},
  year      = {2016},
  abstract  = {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.},
  language  = {en}
}
@article{ValeroBung2018,
  author    = {Valero, Daniel and Bung, Daniel B.},
  title     = {Reformulating self-aeration in hydraulic structures: Turbulent growth of free surface perturbations leading to air entrainment},
  series = {International Journal of Multiphase Flow},
  volume    = {100},
  journal   = {International Journal of Multiphase Flow},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0301-9322},
  doi       = {10.1016/j.ijmultiphaseflow.2017.12.011},
  pages     = {127 -- 142},
  year      = {2018},
  abstract  = {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.},
  language  = {en}
}