@inproceedings{ValeroBungOertel2016, author = {Valero, Daniel and Bung, Daniel Bernhard and Oertel, M.}, title = {Turbulent dispersion in bounded horizontal jets : RANS capabilities and physical modeling comparison}, 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/b21902-13}, pages = {49 -- 55}, year = {2016}, language = {en} } @article{ValeroBungCrookston2018, author = {Valero, Daniel and Bung, Daniel Bernhard and Crookston, B.M.}, title = {Energy dissipation of a Type III basin under design and adverse conditions for stepped and smooth spillways}, series = {Journal of Hydraulic Engineering}, volume = {144}, journal = {Journal of Hydraulic Engineering}, number = {7}, publisher = {ASCE}, address = {Reston, Va.}, issn = {0733-9429}, doi = {10.1061/(ASCE)HY.1943-7900.0001482}, year = {2018}, abstract = {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.}, language = {en} } @article{ValeroBung2018, author = {Valero, Daniel and Bung, Daniel Bernhard}, title = {Vectrino profiler spatial filtering for shear flows based on the mean velocity gradient equation}, series = {Journal of Hydraulic Engineering}, volume = {144}, journal = {Journal of Hydraulic Engineering}, number = {7}, publisher = {ASCE}, address = {Reston, Va.}, issn = {0733-9429}, doi = {10.1061/(ASCE)HY.1943-7900.0001485}, year = {2018}, abstract = {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.}, language = {en} } @inproceedings{ValeroBung2015, author = {Valero, Daniel and Bung, Daniel Bernhard}, title = {Hybrid investigation of air transport processes in moderately sloped stepped spillway flows}, series = {E-proceedings of the 36th IAHR World Congress 28 June - 3 July, 2015, The Hague, the Netherlands}, booktitle = {E-proceedings of the 36th IAHR World Congress 28 June - 3 July, 2015, The Hague, the Netherlands}, organization = {IAHR World Congress <36, 2015, Den Haag>}, pages = {1 -- 10}, year = {2015}, language = {en} } @inproceedings{BungValero2015, author = {Bung, Daniel Bernhard and Valero, Daniel}, title = {Image processing for bubble image velocimetry in self-aerated flows}, series = {E-proceedings of the 36th IAHR World Congress 28 June - 3 July, 2015, The Hague, the Netherlands}, booktitle = {E-proceedings of the 36th IAHR World Congress 28 June - 3 July, 2015, The Hague, the Netherlands}, organization = {IAHR World Congress <36, 2015, Den Haag>}, pages = {1 -- 8}, year = {2015}, language = {en} } @inproceedings{ValeroBung2016, author = {Valero, Daniel and Bung, Daniel Bernhard}, 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{ValeroKramerBungetal.2019, author = {Valero, Daniel and Kramer, Matthias and Bung, Daniel Bernhard 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{ValeroBung2016, author = {Valero, Daniel and Bung, Daniel Bernhard}, 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{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} } @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} }