TY - CHAP A1 - Bung, Daniel B. A1 - Valero, Daniel ED - Dewals, Benjamin T1 - Image processing techniques for velocity estimation in highly aerated flows: bubble image velocimetry vs. optical flow T2 - Sustainable Hydraulics in the Era of Global Change : Proceedings of the 4th IAHR Europe Congress (Liege, Belgium, 27-29 July 2016) Y1 - 2016 SN - 978-1-138-02977-4 SN - 978-1-4987-8149-7 (eBook) U6 - http://dx.doi.org/10.1201/b21902-31 SP - 151 EP - 157 PB - CRC Press ER - TY - BOOK A1 - Bleninger, T. A1 - Brenda, M. A1 - Bung, Daniel B. A1 - Hengl, M. A1 - Schmid, B.H. A1 - Schneider, E. A1 - Sonnenburg, A. A1 - Stoschek, O. T1 - DWA-Regelwerk M 544-1 : Merkblatt: Ausbreitungsprobleme von Einleitungen - Prozesse, Methoden und Modelle - Teil 1: Anwendungsgrundlagen, Schätzformeln und eindimensionale Modelle Y1 - 2016 SN - 978-3-88721-280-3 CY - Hennef ER - TY - CHAP A1 - Valero, Daniel A1 - Bung, Daniel B. A1 - Oertel, M. ED - Dewals, Benjamin T1 - Turbulent dispersion in bounded horizontal jets : RANS capabilities and physical modeling comparison T2 - Sustainable Hydraulics in the Era of Global Change : Proceedings of the 4th IAHR Europe Congress (Liege, Belgium, 27-29 July 2016) Y1 - 2016 SN - 978-1-138-02977-4 SN - 978-1-4987-8149-7 (eBook) U6 - http://dx.doi.org/10.1201/b21902-13 SP - 49 EP - 55 PB - CRC Press ER - TY - CHAP A1 - Valero, Daniel A1 - Bung, Daniel B. T1 - Interfacial velocity estimation in highly aerated stepped spillway flows with a single tip fibre optical probe and Artificial Neural Networks T2 - 6th IAHR International Junior Researcher and Engineer Workshop on Hydraulic Structures, May 30th to June 1st 2016. Lübeck, Germany N2 - Air-water flows can be found in different engineering applications: from nuclear engineering to huge hydraulic structures. In this paper, a single tip fibre optical probe has been used to record high frequency (over 1 MHz) phase functions at different locations of a stepped spillway. These phase functions have been related to the interfacial velocities by means of Artificial Neural Networks (ANN) and the measurements of a classical double tip conductivity probe. Special attention has been put to the input selection and the ANN dimensions. Finally, ANN have shown to be able to link the signal rising times and plateau shapes to the air-water interfacial velocity. Y1 - 2016 U6 - http://dx.doi.org/10.15142/T3Q590 ER - TY - BOOK A1 - Bleninger, T. A1 - Brenda, M. A1 - Bung, Daniel B. A1 - Hengl, M. A1 - Schmid, B.H. A1 - Schneider, E. A1 - Sonnenburg, A. A1 - Stoschek, O. T1 - DWA-Regelwerk M 544-2 : Merkblatt: Ausbreitungsprobleme von Einleitungen - Prozesse, Methoden und Modelle - Teil 2: Mehrdimensionale Modelle Y1 - 2016 SN - 978-3-88721-281-0 CY - Hennef 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 - 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 -