@article{ValeroBung2018, author = {Valero, Daniel and Bung, Daniel B.}, 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{BienerSasseWernhoff2003, author = {Biener, Ernst and Sasse, T. and Wernhoff, T.}, title = {Using harbour dredged material for combination sealing of the former Bockhorner Weg disposal site in Bremen, Germany}, series = {Proceedings of the International Harbour Congress. 13 (2003)}, journal = {Proceedings of the International Harbour Congress. 13 (2003)}, pages = {101 -- 109}, year = {2003}, language = {en} } @article{ValeroBungErpicumetal.2022, author = {Valero, Daniel and Bung, Daniel B. and Erpicum, Sebastien and Peltier, Yann and Dewals, Benjamin}, title = {Unsteady shallow meandering flows in rectangular reservoirs: a modal analysis of URANS modelling}, series = {Journal of Hydro-environment Research}, journal = {Journal of Hydro-environment Research}, number = {In Press}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1570-6443}, doi = {10.1016/j.jher.2022.03.002}, year = {2022}, abstract = {Shallow flows are common in natural and human-made environments. Even for simple rectangular shallow reservoirs, recent laboratory experiments show that the developing flow fields are particularly complex, involving large-scale turbulent structures. For specific combinations of reservoir size and hydraulic conditions, a meandering jet can be observed. While some aspects of this pseudo-2D flow pattern can be reproduced using a 2D numerical model, new 3D simulations, based on the unsteady Reynolds-Averaged Navier-Stokes equations, show consistent advantages as presented herein. A Proper Orthogonal Decomposition was used to characterize the four most energetic modes of the meandering jet at the free surface level, allowing comparison against experimental data and 2D (depth-averaged) numerical results. Three different isotropic eddy viscosity models (RNG k-ε, k-ε, k-ω) were tested. The 3D models accurately predicted the frequency of the modes, whereas the amplitudes of the modes and associated energy were damped for the friction-dominant cases and augmented for non-frictional ones. The performance of the three turbulence models remained essentially similar, with slightly better predictions by RNG k-ε model in the case with the highest Reynolds number. Finally, the Q-criterion was used to identify vortices and study their dynamics, assisting on the identification of the differences between: i) the three-dimensional phenomenon (here reproduced), ii) its two-dimensional footprint in the free surface (experimental observations) and iii) the depth-averaged case (represented by 2D models).}, language = {en} } @article{FellinKingKirschetal.2010, author = {Fellin, Wolfgang and King, Julian and Kirsch, Ansgar and Oberguggenberger, Michael}, title = {Uncertainty modelling and sensitivity analysis of tunnel face stability}, series = {Structural safety}, volume = {32}, journal = {Structural safety}, number = {6}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0167-4730}, doi = {10.1016/j.strusafe.2010.06.001}, pages = {402 -- 410}, year = {2010}, abstract = {This paper proposes an approach to the choice and evaluation of engineering models with the aid of a typical application in geotechnics. An important issue in the construction of shallow tunnels, especially in weak ground conditions, is the tunnel face stability. Various theoretical and numerical models for predicting the necessary support pressure have been put forth in the literature. In this paper, we combine laboratory experiments performed at the University of Innsbruck with current methods of uncertainty and sensitivity analysis for assessing adequacy, predictive power and robustness of the models. The major issues are the handling of the twofold uncertainty of test results and of model predictions as well as the decision about what are the influential input parameters.}, language = {en} } @article{BungCrookstonValero2020, author = {Bung, Daniel B. and Crookston, Brian M. and Valero, Daniel}, title = {Turbulent free-surface monitoring with an RGB-D sensor: the hydraulic jump case}, series = {Journal of Hydraulic Research}, journal = {Journal of Hydraulic Research}, publisher = {Taylor \& Francis}, address = {London}, issn = {1814-2079}, doi = {10.1080/00221686.2020.1844810}, year = {2020}, language = {en} } @article{Hoettges1990, author = {H{\"o}ttges, J{\"o}rg}, title = {Turbulence and Mixing Mechanics in Compound Open Channel Flow / Arnold, Uwe; H{\"o}ttges, J{\"o}rg; Rouv{\´e}, Gerhard}, series = {On cutoff ratios of curved channels : paper presented at the 23rd Congress of the IAHR, Ottawa, Canada, August 21 - 25, 1989 / G. J. Klaassen; B. H. J.van Zanten}, journal = {On cutoff ratios of curved channels : paper presented at the 23rd Congress of the IAHR, Ottawa, Canada, August 21 - 25, 1989 / G. J. Klaassen; B. H. J.van Zanten}, publisher = {Delft Hydraulics}, address = {Delft}, year = {1990}, language = {en} } @article{KramerValeroChansonetal.2019, author = {Kramer, Matthias and Valero, Daniel and Chanson, Hubert and Bung, Daniel B.}, 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{DoeringKendrickLawson2013, author = {D{\"o}ring, Bernd and Kendrick, C. and Lawson, R. M.}, title = {Thermal capacity of composite floor slabs}, series = {Energy and buildings}, volume = {Vol. 67}, journal = {Energy and buildings}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1872-6178 (E-Journal); 0378-7788 (Print)}, pages = {531 -- 539}, year = {2013}, language = {en} } @article{DoeringRegerKuhnhenneetal.2015, author = {D{\"o}ring, Bernd and Reger, Vitali and Kuhnhenne, Markus and Feldmann, Markus and Kesti, Jyrki and Lawson, Mark and Botti, Andrea}, title = {Steel solutions for enabling zero-energy buildings}, series = {Steel Construction - Design and Research}, volume = {8}, journal = {Steel Construction - Design and Research}, number = {3}, publisher = {Ernst \& Sohn}, address = {Berlin}, issn = {1867-0539}, doi = {10.1002/stco.201510029}, pages = {194 -- 200}, year = {2015}, language = {en} } @article{BienerWemhoffBethke1995, author = {Biener, Ernst and Wemhoff, T. and Bethke, H.}, title = {Stability and settlement problems based on the example of the Blockland landfill in Bremen}, series = {Sardinia 95 : Fifth International Landfill Symposium ; (2 - 6 October 1995, S. Margheritadi Pula - Cagliari, Sardinia, Italy) ; proceedings / coord.: Thomas H. Christensen ... - Bd. 2 : Siting, lining, drainage \& landfill mechanics}, journal = {Sardinia 95 : Fifth International Landfill Symposium ; (2 - 6 October 1995, S. Margheritadi Pula - Cagliari, Sardinia, Italy) ; proceedings / coord.: Thomas H. Christensen ... - Bd. 2 : Siting, lining, drainage \& landfill mechanics}, publisher = {CISA, Environmental Sanitary Engineering Centre}, address = {Cagliari}, pages = {843 -- 853}, year = {1995}, language = {en} } @article{OertelBung2015, author = {Oertel, Mario and Bung, Daniel B.}, title = {Stability and scour development of bed material on crossbar block ramps}, series = {International journal of sediment research}, volume = {30}, journal = {International journal of sediment research}, number = {4}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1001-6279}, doi = {10.1016/j.ijsrc.2014.12.003}, pages = {344 -- 350}, year = {2015}, abstract = {Block ramps are ecologically oriented drop structures with adequate energy dissipation and partially moderate flow velocities. A special case is given with crossbar block ramps, where the upstream and downstream level difference is reduced by a series of basins. To prevent the total structure from failing, the stability of single boulders within the crossbars and the bed material in between must be guaranteed. The present paper addresses the stability of bed material and scour development for various flow regimes. Any bed material erosion may affect the stability of the crossbar boulders, which in turn can result in major damages of the ramp. Therefore new design approaches are developed to choose an appropriate bed material size and to avoid failures of crossbar block ramp structures.}, language = {en} } @article{KolymbasFellinKirsch2006, author = {Kolymbas, Dimitrios and Fellin, W. and Kirsch, Ansgar}, title = {Squeezing due to stress relaxation in foliated rock}, series = {International journal for numerical and analytical methods in geomechanics}, volume = {Vol. 30}, journal = {International journal for numerical and analytical methods in geomechanics}, number = {Iss. 13}, issn = {1096-9853 (E-Journal); 0363-9061 (Print)}, doi = {10.1002/nag.530}, pages = {1357 -- 1367}, year = {2006}, 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{ValeroChansonBung2019, author = {Valero, Daniel and Chanson, Hubert and Bung, Daniel B.}, title = {Robust estimators for turbulence properties assessment}, pages = {1 -- 24}, year = {2019}, language = {en} } @article{ValeroChansonBung2020, author = {Valero, Daniel and Chanson, Hubert and Bung, Daniel B.}, 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{KirsteinMuellerWaleckiMingersetal.2012, author = {Kirstein, Simon and M{\"u}ller, Karsten and Walecki-Mingers, Mark and Deserno, Thomas M.}, title = {Robust adaptive flow line detection in sewer pipes}, series = {Automation in construction}, journal = {Automation in construction}, number = {21}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1872-7891 (E-Journal) ; 0926-5805 (Print)}, doi = {10.1016/j.autcon.2011.05.009}, pages = {24 -- 31}, year = {2012}, abstract = {As part of a novel approach to automatic sewer inspection, this paper presents a robust algorithm for automatic flow line detection. A large image repository is obtained from about 50,000 m sewers to represent the high variability of real world sewer systems. Automatic image processing combines Canny edge detection, Hough transform for straight lines and cost minimization using Dijkstra's shortest path algorithm. Assuming that flow lines are mostly smoothly connected horizontal structures, piecewise flow line delineation is reduced to a process of selecting adjacent line candidates. Costs are derived from the gap between adjacent candidates and their reliability. A single parameter α enables simple control of the algorithm. The detected flow line may precisely follow the segmented edges (α = 0.0) or minimize gaps at joints (α = 1.0). Both, manual and ground truth-based analysis indicate that α = 0.8 is optimal and independent of the sewer's material. The algorithm forms an essential step to further automation of sewer inspection.}, language = {en} } @article{Biener1985, author = {Biener, Ernst}, title = {Rehabilitation of old gravity dams}, series = {[Transactions] : proceedings of fifteenth international congress on large dams ; 24 - 28 Juin 1985, Lausanne, Suisse = Quinzieme Congres International des Grands Barrages. - Bd. 4}, journal = {[Transactions] : proceedings of fifteenth international congress on large dams ; 24 - 28 Juin 1985, Lausanne, Suisse = Quinzieme Congres International des Grands Barrages. - Bd. 4}, publisher = {Intern. Commission on Large Dams}, address = {Paris}, pages = {Q 59, R.2, S. 21 -- 23}, year = {1985}, 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} } @article{BungValero2018, author = {Bung, Daniel B. 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{BienerSasse1993, author = {Biener, Ernst and Sasse, T.}, title = {Quality improvements in the construction of multilayer covers}, series = {G{\´e}ologie et confinement des d{\´e}chets toxiques : actes du symposium international, 8 - 11 juin 1993 / GEOCONFINE 93, Montpellier, France. R{\´e}d. Marcel Arnould}, journal = {G{\´e}ologie et confinement des d{\´e}chets toxiques : actes du symposium international, 8 - 11 juin 1993 / GEOCONFINE 93, Montpellier, France. R{\´e}d. Marcel Arnould}, publisher = {Balkema}, address = {Rotterdam [u.a.]}, isbn = {90-5410-330-2}, pages = {309 -- 312}, year = {1993}, language = {en} }