TY - JOUR A1 - Bung, Daniel B. A1 - Valero, Daniel T1 - Optical flow estimation in aerated flows JF - Journal of Hydraulic Research N2 - 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. Y1 - 2016 U6 - http://dx.doi.org/10.1080/00221686.2016.1173600 VL - 54 IS - 5 SP - 575 EP - 580 PB - Taylor & Francis CY - London ER - TY - JOUR A1 - Lopes, Pedro A1 - Leandro, Jorge A1 - Carvalho, Rita F. A1 - Bung, Daniel B. T1 - Alternating skimming flow over a stepped spillway JF - Environmental Fluid Mechanics Y1 - 2017 U6 - http://dx.doi.org/10.1007/s10652-016-9484-x SN - 1573-1510 VL - 17 IS - 2 SP - 303 EP - 322 PB - Springer CY - Berlin ER - TY - JOUR A1 - Hebel, Christoph T1 - Erfahrungen mit der RIN und aktuelle Weiterentwicklungen JF - Straßenverkehrstechnik: Organ der Forschungsgesellschaft für Straßen- und Verkehrswesen, der Bundesvereinigung der Straßenbau- und Verkehrsingenieure und der Österreichischen Forschungsgesellschaft Straße und Verkehr; Zeitschrift für Verkehrsplanung, Verkehrsmanagement, Verkehrssicherheit, Verkehrstechnik Y1 - 2017 SN - 0039-2219 N1 - gedruckt in der Bereichsbibliothek Bayernallee vorhanden VL - 61 IS - 7 SP - 443 EP - 448 PB - Kirschbaum-Verlag CY - Bonn ER - TY - JOUR A1 - Höttges, Jörg T1 - QKan - Management of drainage system data with QGIS JF - Free and Open Source Software for Geospatial (FOSS4G) Conference Proceedings Y1 - 2017 VL - 17 IS - Article 13 SP - 95 EP - 100 ER - TY - THES A1 - Mainz, Stefan T1 - Zur Berechnung der Tragfähigkeit von dünnwandigen Koppelpfetten aus Kaltprofilen für Biegung um die schwache Achse und Torsion Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:1373-opus-3798 CY - Hamburg ER - TY - BOOK A1 - Uibel, Thomas A1 - Peterson, Leif Arne ED - Uibel, Thomas ED - Peterson, Leif Arne T1 - Tagungsband Aachener Holzbautagung 2017 Y1 - 2017 SN - 2197-4489 PB - FH Aachen CY - Aachen ER - TY - JOUR A1 - Laumann, Jörg A1 - Mainz, Stefan A1 - Krahwinkel, Manuel T1 - Traglastuntersuchungen an Koppelpfetten bei Biegung um die schwache Achse und Torsion JF - Stahlbau Y1 - 2017 U6 - http://dx.doi.org/10.1002/stab.201710544 SN - 0038-9145 VL - 86 IS - 11 SP - 1005 EP - 1016 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Valero, Daniel A1 - Bung, Daniel B. T1 - Artificial Neural Networks and pattern recognition for air-water flow velocity estimation using a single-tip optical fibre probe JF - Journal of Hydro-environment Research Y1 - 2017 U6 - http://dx.doi.org/10.1016/j.jher.2017.08.004 SN - 1570-6443 VL - 19 IS - 3 SP - 150 EP - 159 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Kerpen, Nils B. A1 - Bung, Daniel B. A1 - Valero, Daniel A1 - Schlurmann, Torsten T1 - Energy dissipation within the wave run-up at stepped revetments JF - Journal of Ocean University of China Y1 - 2017 U6 - http://dx.doi.org/10.1007/s11802-017-3355-z SN - 1993-5021 VL - 16 IS - 4 SP - 649 EP - 654 PB - Springer CY - Berlin ER - TY - CHAP A1 - Valero, Daniel A1 - Bung, Daniel B. A1 - Erpicum, Sebastien A1 - Dewals, Benjamin T1 - Numerical study of turbulent oscillations around a cylinder: RANS capabilities and sensitivity analysis T2 - Proceedings of the 37th IAHR World Congress August 13 – 18, 2017, Kuala Lumpur, Malaysia Y1 - 2017 SN - 2521-716X SP - 3126 EP - 3135 ER - TY - CHAP A1 - Bung, Daniel B. A1 - Valero, Daniel T1 - FlowCV - An open-source toolbox for computer vision applications in turbulent flows T2 - Proceedings of the 37th IAHR World Congress August 13 – 18, 2017, Kuala Lumpur, Malaysia Y1 - 2017 SN - 2521-716X SP - 5356 EP - 5365 ER - TY - JOUR A1 - Peterson, Leif Arne A1 - Röth, Thilo A1 - Uibel, Thomas T1 - Einsatz von Holzwerkstoffen in Fahrzeugstrukturen JF - Bauen mit Holz Y1 - 2017 SN - 0005-6545 N1 - gedruckt in der Bereichsbibliothek Bayernallee IS - 3 SP - 32 EP - 38 PB - Bruderverlag CY - Köln ER - TY - CHAP A1 - Peterson, Leif Arne A1 - Röth, Thilo A1 - Uibel, Thomas ED - Uibel, Thormas ED - Peterson, Leif Arne ED - Baumann, Marcus T1 - Holzwerkstoffe in Karosseriestrukturen T2 - Tagungsband Aachener Holzbautagung 2017 Y1 - 2017 SN - 2197-4489 SP - 34 EP - 45 ER - TY - JOUR A1 - Kerres, Karsten A1 - Siekmann, Marko T1 - Wie kommuniziere ich prognosegestützte Instandhaltungsstrategien erfolgreich in politischen Entscheidungsgremien? JF - 3 R. Fachzeitschrift für sichere und effiziente Rohleitungssysteme Y1 - 2018 SN - 2191-9798 IS - 12 SP - 47 EP - 51 PB - Vulkan-Verl. CY - Essen ER - TY - JOUR A1 - Wolisz, Henryk A1 - Schütz, Thomas A1 - Blanke, Tobias A1 - Hagenkamp, Markus A1 - Kohrn, Markus A1 - Wesseling, Mark A1 - Müller, Dirk T1 - Cost optimal sizing of smart buildings' energy system components considering changing end-consumer electricity markets JF - Energy Y1 - 2017 U6 - http://dx.doi.org/10.1016/j.energy.2017.06.025 VL - 137 SP - 715 EP - 728 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Valero, Daniel A1 - Bung, Daniel B. T1 - Reformulating self-aeration in hydraulic structures: Turbulent growth of free surface perturbations leading to air entrainment JF - International Journal of Multiphase Flow N2 - 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. Y1 - 2018 U6 - http://dx.doi.org/10.1016/j.ijmultiphaseflow.2017.12.011 SN - 0301-9322 VL - 100 SP - 127 EP - 142 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Valero, Daniel A1 - Bung, Daniel B. T1 - Vectrino profiler spatial filtering for shear flows based on the mean velocity gradient equation JF - Journal of Hydraulic Engineering N2 - 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. Y1 - 2018 U6 - http://dx.doi.org/10.1061/(ASCE)HY.1943-7900.0001485 SN - 0733-9429 N1 - Article number 04018037 VL - 144 IS - 7 PB - ASCE CY - Reston, Va. ER - TY - JOUR A1 - Valero, Daniel A1 - Bung, Daniel B. A1 - Crookston, B.M. T1 - Energy dissipation of a Type III basin under design and adverse conditions for stepped and smooth spillways JF - Journal of Hydraulic Engineering N2 - 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. Y1 - 2018 U6 - http://dx.doi.org/10.1061/(ASCE)HY.1943-7900.0001482 SN - 0733-9429 N1 - Article number 04018036 VL - 144 IS - 7 PB - ASCE CY - Reston, Va. ER - TY - JOUR A1 - Zhang, G. A1 - Valero, Daniel A1 - Bung, Daniel B. A1 - Chanson, H. T1 - On the estimation of free-surface turbulence using ultrasonic sensors JF - Flow Measurement and Instrumentation N2 - 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. Y1 - 2018 U6 - http://dx.doi.org/10.1016/j.flowmeasinst.2018.02.009 SN - 0955-5986 VL - 60 SP - 171 EP - 184 PB - Elsevier CY - Amsterdam ER - TY - BOOK A1 - Jochim, Haldor E. A1 - Lademann, Frank T1 - Planung von Bahnanlagen: Grundlagen - Planung - Berechnung Y1 - 2018 SN - 978-3-446-44220-7 U6 - http://dx.doi.org/10.3139/9783446448940 PB - Fachbuchverlag Leipzig im Carl Hanser Verlag CY - München ET - 2., aktualisierte und erweiterte Auflage ER -