@article{ValeroChansonBung2020, author = {Valero, Daniel and Chanson, Hubert and Bung, Daniel Bernhard}, 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} } @article{ValeroBungCrookston2019, author = {Valero, D. and Bung, Daniel Bernhard 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{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{LopesLeandroCarvalhoetal.2017, author = {Lopes, Pedro and Leandro, Jorge and Carvalho, Rita F. and Bung, Daniel Bernhard}, 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{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} } @incollection{Bung2015, author = {Bung, Daniel Bernhard}, title = {Laboratory models of free-surface flows}, series = {Rivers - physical, fluvial and environmental processes}, booktitle = {Rivers - physical, fluvial and environmental processes}, editor = {Rowinski, Pawel}, publisher = {Springer}, address = {Cham}, isbn = {978-3-319-17718-2 ; 978-3-319-17719-9}, doi = {10.1007/978-3-319-17719-9_9}, pages = {213 -- 228}, year = {2015}, abstract = {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.}, 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} } @incollection{ChansonBungMatos2015, author = {Chanson, Hubert and Bung, Daniel Bernhard and Matos, J.}, title = {Stepped spillways and cascades}, series = {Energy dissipation in hydraulic structures / Hubert Chanson (ed.)}, booktitle = {Energy dissipation in hydraulic structures / Hubert Chanson (ed.)}, publisher = {CRC Press}, address = {Boca Raton, Fla. [u.a.]}, isbn = {978-1-138-02755-8 (print) ; 978-1-315-68029-3 (e-Book)}, pages = {45 -- 64}, year = {2015}, language = {en} } @inproceedings{BuehlerLeandroBungetal.2015, author = {B{\"u}hler, P. and Leandro, J. and Bung, Daniel Bernhard and Lopes, P. and Carvalho, R.}, title = {Measuring void fraction of a stepped spillway with non-intrusive methods using different image resolutions}, series = {2nd International Workshop on Hydraulic Structures : Data Validation : Coimbra, Portugal, 8-9 May 2015}, booktitle = {2nd International Workshop on Hydraulic Structures : Data Validation : Coimbra, Portugal, 8-9 May 2015}, organization = {International Workshop on Hydraulic Structures : Data Validation <2, 2015, Coimbra>}, pages = {1 -- 8}, year = {2015}, language = {en} }