@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} } @article{Hebel2017, author = {Hebel, Christoph}, title = {Erfahrungen mit der RIN und aktuelle Weiterentwicklungen}, series = {Straßenverkehrstechnik: Organ der Forschungsgesellschaft f{\"u}r Straßen- und Verkehrswesen, der Bundesvereinigung der Straßenbau- und Verkehrsingenieure und der {\"O}sterreichischen Forschungsgesellschaft Straße und Verkehr; Zeitschrift f{\"u}r Verkehrsplanung, Verkehrsmanagement, Verkehrssicherheit, Verkehrstechnik}, volume = {61}, journal = {Straßenverkehrstechnik: Organ der Forschungsgesellschaft f{\"u}r Straßen- und Verkehrswesen, der Bundesvereinigung der Straßenbau- und Verkehrsingenieure und der {\"O}sterreichischen Forschungsgesellschaft Straße und Verkehr; Zeitschrift f{\"u}r Verkehrsplanung, Verkehrsmanagement, Verkehrssicherheit, Verkehrstechnik}, number = {7}, publisher = {Kirschbaum-Verlag}, address = {Bonn}, issn = {0039-2219}, pages = {443 -- 448}, year = {2017}, language = {de} } @article{PetersonRoethUibel2017, author = {Peterson, Leif Arne and R{\"o}th, Thilo and Uibel, Thomas}, title = {Einsatz von Holzwerkstoffen in Fahrzeugstrukturen}, series = {Bauen mit Holz}, journal = {Bauen mit Holz}, number = {3}, publisher = {Bruderverlag}, address = {K{\"o}ln}, issn = {0005-6545}, pages = {32 -- 38}, year = {2017}, language = {de} } @article{Uibel2016, author = {Uibel, Thomas}, title = {Untersuchungen zum Spaltverhalten von Holzschrauben. Teil 1}, series = {Bauen mit Holz}, journal = {Bauen mit Holz}, number = {10}, publisher = {Rudolf M{\"u}ller}, address = {K{\"o}ln}, issn = {0005-6545}, pages = {40 -- 42}, year = {2016}, language = {de} } @article{MoorkampPetersonUibel2016, author = {Moorkamp, Wilfried and Peterson, Leif Arne and Uibel, Thomas}, title = {Mit guten Aussichten. Bericht {\"u}ber den Studiengang Holzingenieurwesen an der FH Aachen}, series = {Bauen mit Holz}, journal = {Bauen mit Holz}, number = {5}, publisher = {Rudolf M{\"u}ller}, address = {K{\"o}ln}, issn = {0005-6545}, pages = {33 -- 36}, year = {2016}, language = {de} } @article{LaumannMainzKrahwinkel2017, author = {Laumann, J{\"o}rg and Mainz, Stefan and Krahwinkel, Manuel}, title = {Traglastuntersuchungen an Koppelpfetten bei Biegung um die schwache Achse und Torsion}, series = {Stahlbau}, volume = {86}, journal = {Stahlbau}, number = {11}, publisher = {Wiley}, address = {Weinheim}, issn = {0038-9145}, doi = {10.1002/stab.201710544}, pages = {1005 -- 1016}, year = {2017}, language = {de} } @article{ValeroBung2018, author = {Valero, Daniel and Bung, Daniel Bernhard}, 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{ValeroBung2017, author = {Valero, Daniel and Bung, Daniel Bernhard}, title = {Artificial Neural Networks and pattern recognition for air-water flow velocity estimation using a single-tip optical fibre probe}, series = {Journal of Hydro-environment Research}, volume = {19}, journal = {Journal of Hydro-environment Research}, number = {3}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1570-6443}, doi = {10.1016/j.jher.2017.08.004}, pages = {150 -- 159}, year = {2017}, language = {en} } @article{KerpenBungValeroetal.2017, 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 = {Journal of Ocean University of China}, volume = {16}, journal = {Journal of Ocean University of China}, number = {4}, publisher = {Springer}, address = {Berlin}, issn = {1993-5021}, doi = {10.1007/s11802-017-3355-z}, pages = {649 -- 654}, year = {2017}, 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} }