@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{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{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}
}
@inproceedings{ValeroBungCrookstonetal.2016,
  author    = {Valero, Daniel and Bung, Daniel Bernhard 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}
}
@inproceedings{BungValero2016,
  author    = {Bung, Daniel Bernhard and Valero, Daniel},
  title     = {Application of the optical flow method to velocity determination in hydraulic structure models},
  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/T3150628160853},
  pages     = {223 -- 232},
  year      = {2016},
  language  = {en}
}
@inproceedings{OertelBung2016,
  author    = {Oertel, M. and Bung, Daniel Bernhard},
  title     = {Scouring processes downstream a crossbar block ramp},
  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/T3340628160853},
  pages     = {549 -- 559},
  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{ValeroBung2016,
  author    = {Valero, Daniel and Bung, Daniel Bernhard},
  title     = {Development of the interfacial air layer in the non-aerated region of high-velocity spillway flows: Instabilities growth, entrapped air and influence on the self-aeration onset},
  series = {International Journal of Multiphase Flow},
  volume    = {84},
  journal   = {International Journal of Multiphase Flow},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0301-9322},
  doi       = {10.1016/j.ijmultiphaseflow.2016.04.012},
  pages     = {66 -- 74},
  year      = {2016},
  abstract  = {Self-aeration is traditionally explained by the water turbulent boundary layer outer edge intersection with the free surface. This paper presents a discussion on the commonly accepted hypothesis behind the computation of the critical point of self-aeration in spillway flows and a new formulation is proposed based on the existence of a developing air flow over the free surface. Upstream of the inception point of self-aeration, some surface roughening has been often reported in previous studies which consequently implies some entrapped air transport and air-water flows coupling. Such air flow is proven in this study by presenting measured air velocities and computing the air boundary layer thickness for a 1V:2H smooth chute flow. Additionally, the growth rate of free surface waves has been analysed by means of Ultrasonic Sensors measurements, obtaining also the entrapped air concentration. High-speed camera imaging has been used for qualitative study of the flow perturbations.},
  language  = {en}
}
@article{ZhangValeroBungetal.2018,
  author    = {Zhang, G. and Valero, Daniel and Bung, Daniel Bernhard 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{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{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}
}
@inproceedings{BungOertel2019,
  author    = {Bung, Daniel Bernhard and Oertel, Mario},
  title     = {Wave breaking over a submerged horizontal plate: Optical Flow, LES and RANS},
  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       = {10.3850/38WC092019-0509},
  pages     = {3690 -- 3698},
  year      = {2019},
  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}
}
@inproceedings{TullisCrookstonBung2019,
  author    = {Tullis, Blake P. and Crookston, Brian M. and Bung, Daniel Bernhard},
  title     = {Weir head-discharge relationships: A multi-lab exercise},
  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},
  pages     = {1 -- 15},
  year      = {2019},
  language  = {en}
}
@article{BlankeHagenkampDoeringetal.2021,
  author    = {Blanke, Tobias and Hagenkamp, Markus and D{\"o}ring, Bernd and G{\"o}ttsche, Joachim and Reger, Vitali and Kuhnhenne, Markus},
  title     = {Net-exergetic, hydraulic and thermal optimization of coaxial heat exchangers using fixed flow conditions instead of fixed flow rates},
  series = {Geothermal Energy},
  volume    = {9},
  journal   = {Geothermal Energy},
  number    = {Article number: 19},
  publisher = {Springer},
  address   = {Berlin},
  issn      = {2195-9706},
  doi       = {10.1186/s40517-021-00201-3},
  pages     = {23 Seiten},
  year      = {2021},
  abstract  = {Previous studies optimized the dimensions of coaxial heat exchangers using constant mass fow rates as a boundary condition. They show a thermal optimal circular ring width of nearly zero. Hydraulically optimal is an inner to outer pipe radius ratio of 0.65 for turbulent and 0.68 for laminar fow types. In contrast, in this study, fow conditions in the circular ring are kept constant (a set of fxed Reynolds numbers) during optimization. This approach ensures fxed fow conditions and prevents inappropriately high or low mass fow rates. The optimization is carried out for three objectives: Maximum energy gain, minimum hydraulic efort and eventually optimum net-exergy balance. The optimization changes the inner pipe radius and mass fow rate but not the Reynolds number of the circular ring. The thermal calculations base on Hellstr{\"o}m's borehole resistance and the hydraulic optimization on individually calculated linear loss of head coefcients. Increasing the inner pipe radius results in decreased hydraulic losses in the inner pipe but increased losses in the circular ring. The net-exergy diference is a key performance indicator and combines thermal and hydraulic calculations. It is the difference between thermal exergy fux and hydraulic efort. The Reynolds number in the circular ring is instead of the mass fow rate constant during all optimizations. The result from a thermal perspective is an optimal width of the circular ring of nearly zero. The hydraulically optimal inner pipe radius is 54\% of the outer pipe radius for laminar fow and 60\% for turbulent fow scenarios. Net-exergetic optimization shows a predominant infuence of hydraulic losses, especially for small temperature gains. The exact result depends on the earth's thermal properties and the fow type. Conclusively, coaxial geothermal probes' design should focus on the hydraulic optimum and take the thermal optimum as a secondary criterion due to the dominating hydraulics.},
  language  = {en}
}
@inproceedings{MerkensHebel2021,
  author    = {Merkens, Torsten and Hebel, Christoph},
  title     = {Sharing mobility concepts - flexible, sustainable, smart},
  series = {Proceedings of the 1st UNITED - Southeast Asia Automotive Interest Group (SAIG) International Conference},
  booktitle = {Proceedings of the 1st UNITED - Southeast Asia Automotive Interest Group (SAIG) International Conference},
  isbn      = {978-3-902103-94-9},
  pages     = {43 -- 44},
  year      = {2021},
  language  = {en}
}
@article{ValeroSchalkoFriedrichetal.2021,
  author    = {Valero, Daniel and Schalko, Isabella and Friedrich, Heide and Abad, Jorge D. and Bung, Daniel Bernhard 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{BungValero2016,
  author    = {Bung, Daniel Bernhard 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}
}
@inproceedings{KerpenBungValeroetal.2016,
  author    = {Kerpen, Nils B. and Bung, Daniel Bernhard and Valero, Daniel and Schlurmann, Torsten},
  title     = {Energy dissipation within the wave run-up at stepped revetments},
  series = {8th Chinese-German Joint Symposium on Hydraulic and Ocean Engineering, Qingdao, China},
  booktitle = {8th Chinese-German Joint Symposium on Hydraulic and Ocean Engineering, Qingdao, China},
  pages     = {6 Seiten},
  year      = {2016},
  language  = {en}
}
@inproceedings{BungValero2016,
  author    = {Bung, Daniel Bernhard 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}
}