@inproceedings{BungValero2016,
  author    = {Bung, Daniel B. and Valero, Daniel},
  title     = {Image processing techniques for velocity estimation in highly aerated flows: bubble image velocimetry vs. optical flow},
  series = {Sustainable Hydraulics in the Era of Global Change : Proceedings of the 4th IAHR Europe Congress (Liege, Belgium, 27-29 July 2016)},
  booktitle = {Sustainable Hydraulics in the Era of Global Change : Proceedings of the 4th IAHR Europe Congress (Liege, Belgium, 27-29 July 2016)},
  editor    = {Dewals, Benjamin},
  publisher = {CRC Press},
  isbn      = {978-1-138-02977-4},
  doi       = {10.1201/b21902-31},
  pages     = {151 -- 157},
  year      = {2016},
  language  = {en}
}
@inproceedings{ValeroBung2016,
  author    = {Valero, Daniel and Bung, Daniel B.},
  title     = {Interfacial velocity estimation in highly aerated stepped spillway flows with a single tip fibre optical probe and Artificial Neural Networks},
  series = {6th IAHR International Junior Researcher and Engineer Workshop on Hydraulic Structures, May 30th to June 1st 2016. L{\"u}beck, Germany},
  booktitle = {6th IAHR International Junior Researcher and Engineer Workshop on Hydraulic Structures, May 30th to June 1st 2016. L{\"u}beck, Germany},
  doi       = {10.15142/T3Q590},
  pages     = {13 Seiten},
  year      = {2016},
  abstract  = {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.},
  language  = {en}
}
@inproceedings{ValeroBungCrookstonetal.2016,
  author    = {Valero, Daniel and Bung, Daniel B. and Crookston, B. M. and Matos, J.},
  title     = {Numerical investigation of USBR type III stilling basin performance downstream of smooth and stepped spillways},
  series = {Hydraulic Structures and Water System Management. 6th IAHR International Symposium on Hydraulic Structures, Portland, OR, 27-30 June 2016},
  booktitle = {Hydraulic Structures and Water System Management. 6th IAHR International Symposium on Hydraulic Structures, Portland, OR, 27-30 June 2016},
  editor    = {Crookston, B. and Tullis, B.},
  isbn      = {978-1-884575-75-4},
  doi       = {10.15142/T340628160853},
  pages     = {635 -- 646},
  year      = {2016},
  language  = {en}
}
@article{ValeroVitiGualtieri2019,
  author    = {Valero, Daniel and Viti, Nicolo and Gualtieri, Carlo},
  title     = {Numerical Simulation of Hydraulic Jumps. Part 1: Experimental Data for Modelling Performance Assessment},
  series = {Water},
  volume    = {11},
  journal   = {Water},
  number    = {1},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2073-4441},
  doi       = {10.3390/w11010036},
  pages     = {Art. Nr. 36},
  year      = {2019},
  language  = {en}
}
@article{VitiValeroGualtieri2019,
  author    = {Viti, Nicolo and Valero, Daniel and Gualtieri, Carlo},
  title     = {Numerical Simulation of Hydraulic Jumps. Part 2: Recent Results and Future Outlook},
  series = {Water},
  volume    = {11},
  journal   = {Water},
  number    = {1},
  issn      = {2073-4441},
  doi       = {10.3390/w11010028},
  pages     = {Art. Nr. 28},
  year      = {2019},
  language  = {en}
}
@inproceedings{ValeroBungErpicumetal.2017,
  author    = {Valero, Daniel and Bung, Daniel B. and Erpicum, Sebastien and Dewals, Benjamin},
  title     = {Numerical study of turbulent oscillations around a cylinder: RANS capabilities and sensitivity analysis},
  series = {Proceedings of the 37th IAHR World Congress August 13 - 18, 2017, Kuala Lumpur, Malaysia},
  booktitle = {Proceedings of the 37th IAHR World Congress August 13 - 18, 2017, Kuala Lumpur, Malaysia},
  issn      = {2521-716X},
  pages     = {3126 -- 3135},
  year      = {2017},
  language  = {en}
}
@article{ZhangValeroBungetal.2018,
  author    = {Zhang, G. and Valero, Daniel and Bung, Daniel B. and Chanson, H.},
  title     = {On the estimation of free-surface turbulence using ultrasonic sensors},
  series = {Flow Measurement and Instrumentation},
  volume    = {60},
  journal   = {Flow Measurement and Instrumentation},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0955-5986},
  doi       = {10.1016/j.flowmeasinst.2018.02.009},
  pages     = {171 -- 184},
  year      = {2018},
  abstract  = {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.},
  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}
}
@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{BayonValeroGarciaBartualetal.2016,
  author    = {Bayon, Arnau and Valero, Daniel and Garcia-Bartual, Rafael and Vall{\´e}s-Mor{\´a}n, Francisco Jos{\´e} and L{\´o}pez-Jim{\´e}nez, P. Amparo},
  title     = {Performance assessment of OpenFOAM and FLOW-3D in the numerical modeling of a low Reynolds number hydraulic jump},
  series = {Environmental Modelling \& Software},
  volume    = {80},
  journal   = {Environmental Modelling \& Software},
  publisher = {Elsevier},
  address   = {Amsterdam},
  isbn      = {1364-8152},
  doi       = {10.1016/j.envsoft.2016.02.018},
  pages     = {322 -- 335},
  year      = {2016},
  abstract  = {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.},
  language  = {en}
}