@article{BungValero2018, author = {Bung, Daniel Bernhard 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} } @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} } @article{ValeroChansonBung2019, author = {Valero, Daniel and Chanson, Hubert and Bung, Daniel Bernhard}, title = {Robust estimators for turbulence properties assessment}, pages = {1 -- 24}, year = {2019}, language = {en} } @article{KramerValeroChansonetal.2019, author = {Kramer, Matthias and Valero, Daniel and Chanson, Hubert and Bung, Daniel Bernhard}, 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{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} } @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} } @article{BungErpicumTullis2020, author = {Bung, Daniel Bernhard and Erpicum, S{\´e}bastien and Tullis, Blanke P.}, title = {Advances in hydraulic structures engineering}, series = {Journal of Hydraulic Engineering}, volume = {147}, journal = {Journal of Hydraulic Engineering}, number = {1}, publisher = {ASCE}, address = {Reston, Va.}, issn = {0733-9429 (Druckausgabe)}, doi = {10.1061/(ASCE)HY.1943-7900.0001851}, pages = {1 Seite}, year = {2020}, language = {en} } @article{KerresGredigkHoffmannJatheetal.2020, author = {Kerres, Karsten and Gredigk-Hoffmann, Sylvia and Jathe, R{\"u}diger and Orlik, Stefan and Sariyildiz, Mustafa and Schmidt, Torsten and Sympher, Klaus-Jochen and Uhlenbroch, Adrian}, title = {Future approaches for sewer system condition assessment}, series = {Water Practice \& Technology}, journal = {Water Practice \& Technology}, number = {15 (2)}, publisher = {IWA Publishing}, address = {London}, issn = {1751-231X}, doi = {10.2166/wpt.2020.027}, pages = {386 -- 393}, year = {2020}, abstract = {Different analytical approaches exist to describe the structural substance or wear reserve of sewer systems. The aim is to convert engineering assessments of often complex defect patterns into computational algorithms and determine a substance class for a sewer section or manhole. This analytically determined information is essential for strategic rehabilitation planning processes up to network level, as it corresponds to the most appropriate rehabilitation type and can thus provide decision-making support. Current calculation methods differ clearly from each other in parts, so that substance classes determined by the different approaches are only partially comparable with each other. The objective of the German R\&D cooperation project 'SubKanS' is to develop a methodology for classifying the specific defect patterns resulting from the interaction of all the individual defects, and their severities and locations. The methodology takes into account the structural substance of sewer sections and manholes, based on real data and theoretical considerations analogous to the condition classification of individual defects. The result is a catalogue of defect patterns and characteristics, as well as associated structural substance classifications of sewer systems (substance classes). The methodology for sewer system substance classification is developed so that the classification of individual defects can be transferred into a substance class of the sewer section or manhole, eventually taking into account further information (e.g. pipe material, nominal diameter, etc.). The result is a validated methodology for automated sewer system substance classification.}, language = {en} }