TY - JOUR A1 - Oertel, Mario A1 - Bung, Daniel B. T1 - Stability and scour development of bed material on crossbar block ramps JF - International journal of sediment research N2 - 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. Y1 - 2015 U6 - http://dx.doi.org/10.1016/j.ijsrc.2014.12.003 SN - 1001-6279 VL - 30 IS - 4 SP - 344 EP - 350 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Bayon, Arnau A1 - Valero, Daniel A1 - Garcia-Bartual, Rafael A1 - Vallés-Morán, Francisco José A1 - López-Jiménez, P. Amparo T1 - Performance assessment of OpenFOAM and FLOW-3D in the numerical modeling of a low Reynolds number hydraulic jump JF - Environmental Modelling & Software N2 - 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. Y1 - 2016 SN - 1364-8152 U6 - http://dx.doi.org/10.1016/j.envsoft.2016.02.018 VL - 80 SP - 322 EP - 335 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Valero, Daniel A1 - Bung, Daniel B. T1 - Sensitivity of turbulent Schmidt number and turbulence model to simulations of jets in crossflow JF - Environmental Modelling and Software N2 - 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. Y1 - 2016 U6 - http://dx.doi.org/10.1016/j.envsoft.2016.04.030 SN - 1364-8152 (electronic) VL - 82 SP - 218 EP - 228 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Valero, Daniel A1 - Bung, Daniel B. T1 - 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 JF - International Journal of Multiphase Flow N2 - 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. Y1 - 2016 U6 - http://dx.doi.org/10.1016/j.ijmultiphaseflow.2016.04.012 SN - 0301-9322 VL - 84 SP - 66 EP - 74 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Reger, V. A1 - Döring, Bernd A1 - Kuhnhenne, M. T1 - Passive und aktive Maßnahmen zur Flächenkühlung im Stahl(leicht)bau JF - Bauingenieur N2 - Mit steigenden Dämmstandards und höheren Komfortanforderungen der Nutzer gerät die Problematik der sommerlichen Überhitzung zunehmend in den Fokus. Um die Überhitzung möglichst gering zu halten, sind Maßnahmen und Lösungen zu entwickeln, die den potenziellen Kühlbedarf eines Gebäudes vermeiden sowie reduzieren. Im Rahmen des europäischen Forschungsprojektes BATIMASS wurden Techniken untersucht, die die sommerliche Raumtemperatur ohne zusätzliche Kühlung (passiv) oder aber mit energieeffizienter wasserbasierter Flächenkühlung (aktiv) reduzieren und die besonders für Gebäude in Stahl(leicht)bauweise geeignet sind. Dafür wurde die Methodik der thermisch äquivalenten Decke weiterentwickelt, um das thermische Verhalten von Profilblechdecken in Gebäuden für beide Lösungsansätze analysieren zu können. Darüber hinaus wurde der Einsatz von Phasenwechselmaterial (PCM) zur Steigerung der Speicherfähigkeit von leichten Decken mit besonders geringer thermischer Masse in Simulationen sowie im Labor untersucht und bewertet. Y1 - 2016 U6 - http://dx.doi.org/10.37544/0005-6650-2016-07-08-63 SN - 0005-6650 N1 - gedruckt in der Bereichsbibliothek Bayernallee unter der Signatur 13 Z 049 VL - 91 IS - Jul/Aug SP - 309 EP - 316 PB - VDI Fachmedien CY - Düsseldorf ER - TY - JOUR A1 - Uibel, Thomas T1 - Untersuchungen zum Spaltverhalten von Holzschrauben. Teil 1 JF - Bauen mit Holz Y1 - 2016 SN - 0005-6545 N1 - gedruckte Zeitschrift in der Bereichsbibliothek Bayernallee IS - 10 SP - 40 EP - 42 PB - Rudolf Müller CY - Köln ER - TY - JOUR A1 - Moorkamp, Wilfried A1 - Peterson, Leif Arne A1 - Uibel, Thomas T1 - Mit guten Aussichten. Bericht über den Studiengang Holzingenieurwesen an der FH Aachen JF - Bauen mit Holz Y1 - 2016 SN - 0005-6545 N1 - gedruckte Zeitschrift in der Bereichsbibliothek Bayernallee IS - 5 SP - 33 EP - 36 PB - Rudolf Müller CY - Köln ER - TY - JOUR A1 - Hörenbaum, Christoph A1 - Laumann, Jörg A1 - Prokop, Ines T1 - Zur Anwendung des Eurocode 3 Teil 1-2 für die Heißbemessung und Anregungen für dessen Novellierung JF - Stahlbau N2 - Die Eurocodes werden bis zum Jahr 2020 im Europäischen Komitee für Normung (CEN), Technisches Komitee TC 250, überarbeitet. In Vorbereitung auf die Eurocode-Novellierung haben engagierte Ingenieure im Rahmen der Initiative PraxisRegeln Bau (PRB) die für die praktische Anwendung häufig genutzten Teile des Eurocode 3 untersucht. Mit dem Ziel, die Praxistauglichkeit des Eurocode 3 für die Heißbemessung zu verbessern, wurden die bestehende Norm EN 1993 Teil 1-2 insbesondere in Bezug auf die Anwenderfreundlichkeit analysiert und Vorschläge für die europäische Novellierung erarbeitet. Die Analysen zeigen, dass durch Umstrukturierungen und durch die Einführung von Tabellen die Verständlichkeit und Anwenderfreundlichkeit der Regeln für die Heißbemessung bedeutend erhöht werden können. KW - EN 1993-1-2 KW - Tragwerksbemessung KW - Brandfall KW - Forschung, pränormativ KW - structural design Y1 - 2016 U6 - http://dx.doi.org/10.1002/stab.201610382 SN - 1437-1049 VL - 85 IS - 6 SP - 429 EP - 434 PB - Ernst & Sohn GmbH CY - Berlin ER - 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 - 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 - 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 - 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 -