@inproceedings{ValeroBungOertel2016, author = {Valero, Daniel and Bung, Daniel Bernhard and Oertel, M.}, title = {Turbulent dispersion in bounded horizontal jets : RANS capabilities and physical modeling comparison}, 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/b21902-13}, pages = {49 -- 55}, year = {2016}, language = {en} } @techreport{SansomLawsonTuchoetal.2016, author = {Sansom, M. and Lawson, R.M. and Tucho, R. and Kendrick, C. and Ogden, R. and Resalati, S. and Garay, R. and D{\"o}ring, Bernd and Reger, V. and Gilbert, J. and Heikkinen, J. and Hemmila, K.}, title = {Building in active thermal mass into steel structures (BATIMASS) - EUR 28166EN}, publisher = {Publications Office of the European Union}, address = {Luxembourg}, organization = {European Commission}, isbn = {978-92-79-63176-4}, issn = {1831-9424}, doi = {10.2777/25999}, pages = {147 Seiten}, year = {2016}, abstract = {The main objective of the BATIMASS project was to address how the energy balance in relatively lightweight steel buildings can be improved by building in 'active thermal mass' (ATM) into the building fabric. This was achieved through concept design, dynamic thermal modelling and testing of a number of potentially viable systems and concepts. A significant programme of thermal simulation modelling was undertaken utilising the thermally equivalent slab (TES) concept to model the passive thermal capacity effect of profiled, composite metal floor decks. It is apparent from the modelling results that thermal mass is a highly complex phenomenon which is highly dependent upon building type, occupancy patterns, climate and many other aspects of the building design and servicing strategy. The ATM systems developed, both conceptually and for prototype testing, focussed on water-cooled composite slabs, the Cofradal floor system and the phase change material (PCM) Energain. In addition to laboratory testing of prototypes, whole building monitoring was undertaken at the Kubik building in Spain and the RWTH test building in Germany. Advanced thermal modelling was also undertaken to estimate the likely benefits of the ATM concept designs developed and for comparison with the test results. In addition to thermal testing, structural tests were conducted on composite floor specimens incorporating embedded water pipes. This Final Report presents the results of the activities carried out under this RFCS contract RFSR CT 2012 00033. The work carried out is reported in six major sections corresponding to the technical Work Packages of the project. Only summaries of the work carried out are provided in this report; all work undertaken is fully reported in the formal project deliverables.}, language = {en} } @techreport{LawsonBaddooVanieretal.2013, author = {Lawson, R.M. and Baddoo, N.R. and Vanier, G. and D{\"o}ring, Bernd and Kuhnhenne, M. and Nieminen, J. and Beguin, P. and Herbin, S. and Caroli, G. and Adetunji, I. and Kozlowski, A.}, title = {Renovation of buildings using steel technologies (Robust) - EUR 25335}, publisher = {Publications Office of the European Union}, address = {Luxembourg}, organization = {European Commission}, isbn = {978-92-79-24950-1}, issn = {1831-9424}, doi = {10.2777/97860}, pages = {134 Seiten}, year = {2013}, abstract = {Robust addresses the renovation and improvement of existing residential, industrial and commercial buildings using steel-based technologies, focusing on techniques such as over-cladding, over-roofing and roof-top extensions. Steel-intensive renovation techniques currently on the market were reviewed. Performance criteria were developed for over-cladding systems meeting current regulatory standards, with guidelines on how to achieve appropriate levels of air-tightness.}, language = {en} } @techreport{FeldmannKuhnhenneDoeringetal.2013, author = {Feldmann, M. and Kuhnhenne, M. and D{\"o}ring, Bernd and Pyschny, D. and Lawson, R.M. and Chuter, R.D. and Boudjabeur, S. and Lecomte-Labory, F. and Airaksinen, M. and Heikkinen, J. and Laamanen, J. and Albart, P. and D'Haeyer, R. and Chica, J.A. and Maseda, J.M. and Amundarain, A. and Rips, M.O. and Nu{\~n}ez, J.A. and Mac{\´i}as, O. and Beguin, P. and Ben Larbi, A.}, title = {Energy and thermal improvements for construction in steel (ETHICS) - EUR 26010}, publisher = {Publications Office of the European Union}, address = {Luxembourg}, organization = {European Commission}, isbn = {978-92-79-30789-8}, issn = {1831-9424}, doi = {10.2777/17106}, pages = {136 Seiten}, year = {2013}, abstract = {ETHICS is concerned with evaluating, measuring and making improvements in the thermal and energy performance of steel-clad and steel-framed buildings. It addresses basic building physics performance at a laboratory and full-scale level, and the preparation of design guidance for commercial, industrial and residential buildings. It includes the development of design tools to assist users in assessing whole-building performance, and calibrates these tools against whole-building measurements, which will be obtained from this research. Opportunities for renewable energy and other energy-saving features will be assessed. This project focuses on objectives that are of particular interest for the design of new steel constructions regarding energy efficiency. ETHICS investigates the as-built performance by on-site tests regarding air tightness and heat transfer properties of the building envelope and by monitoring the energy consumption and thermal comfort of selected up-to-date steel buildings. As energy efficiency is a key requirement for design and construction of buildings in the future, this project provides well-founded scientific data, which prove the high energy performance of current steel constructions and work out details for further improvements to maintain and extend the position of steel products in the construction sector.}, language = {en} } @techreport{KestiMononenLautsoetal.2015, author = {Kesti, Jyrki and Mononen, Tarmo and Lautso, Petteri and D{\"o}ring, Bernd and Reger, Vitali and Holopainen, R. and Jung, N. and Shemeikka, J. and Nieminen, J. and Reda, F. and Lawson, Mark and Botti, Andrea and Hall, R. and Zold, A. and Buday, T.}, title = {Zero energy solutions for multifunctional steel intensive commercial buildings (ZEMUSIC) - EUR 27627}, publisher = {Publications Office of the European Union}, address = {Luxembourg}, organization = {European Commission}, isbn = {978-92-79-54071-4}, issn = {1831-9424}, doi = {10.2777/111520}, pages = {146 Seiten}, year = {2015}, abstract = {The broad commercial objective of this project was the sustainable value creation in steel building technology by addressing the ways in which significant energy reductions can be made in the operation phase of multi-storey commercial buildings. A review on energy efficient commercial buildings in Europe has been carried out consisting of several case studies from different countries. The project included development of zero-energy concepts for reducing energy demand as well as concepts for heating, cooling and ventilation systems by utilising renewable energy sources in three different climates. Also alternative structural frame solutions were developed and analyzed in respect of structural and MEP (mechanical, electrical and plumbing solutions) features. An innovative long span floor system with integrated MEP routings promises a cost effective alternative for sophisticated ventilation distribution and radiant heating and cooling systems, allowing for high energy efficiency and high quality interior climate. The report includes also review of best architectural practices for integrated renewable energy solutions including different design strategies for building facades of zero energy buildings. Interesting results and design basis are also presented for steel energy pile concept, where structural foundation piles are utilized for ground energy harvesting. Life cycle cost calculations for near zero energy office building based on developed technologies show that a near zero energy construction is also profitable. The results and work methods of the project have been summarized in the form of design guidance that offers designers the knowledge gained in a form that can be easily understood.}, language = {en} } @incollection{FeldmannDoeringPyschny2016, author = {Feldmann, M. and D{\"o}ring, Bernd and Pyschny, D.}, title = {Floor systems; Sustainabilty analyses and assessments of steel bridges}, series = {Sustainable steel buildings : a practical guide for structures and envelopes}, booktitle = {Sustainable steel buildings : a practical guide for structures and envelopes}, publisher = {Wiley Blackwell}, address = {Chichester, West Sussex}, isbn = {978-1-118-74079-8 (PDF)}, pages = {198 -- 223}, year = {2016}, language = {en} } @inproceedings{ValeroBung2016, author = {Valero, Daniel and Bung, Daniel Bernhard}, title = {Interfacial velocity estimation in highly aerated stepped spillway flows with a single tip fibre optical probe and Artificial Neural Networks}, series = {6th IAHR International Junior Researcher and Engineer Workshop on Hydraulic Structures, May 30th to June 1st 2016. L{\"u}beck, Germany}, booktitle = {6th IAHR International Junior Researcher and Engineer Workshop on Hydraulic Structures, May 30th to June 1st 2016. L{\"u}beck, Germany}, doi = {10.15142/T3Q590}, pages = {13 Seiten}, year = {2016}, abstract = {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.}, language = {en} } @article{KramerValeroChansonetal.2019, author = {Kramer, Matthias and Valero, Daniel and Chanson, Hubert and Bung, Daniel Bernhard}, title = {Towards reliable turbulence estimations with phase-detection probes: an adaptive window cross-correlation technique}, series = {Experiments in Fluids}, volume = {60}, journal = {Experiments in Fluids}, publisher = {Springer}, address = {Berlin}, issn = {1432-1114}, doi = {10.1007/s00348-018-2650-9}, year = {2019}, language = {en} } @article{BungCrookstonValero2020, author = {Bung, Daniel Bernhard and Crookston, Brian M. and Valero, Daniel}, title = {Turbulent free-surface monitoring with an RGB-D sensor: the hydraulic jump case}, series = {Journal of Hydraulic Research}, journal = {Journal of Hydraulic Research}, publisher = {Taylor \& Francis}, address = {London}, issn = {1814-2079}, doi = {10.1080/00221686.2020.1844810}, year = {2020}, language = {en} } @article{ErpicumCrookstonBombardellietal.2021, author = {Erpicum, Sebastien and Crookston, Brian M. and Bombardelli, Fabian and Bung, Daniel Bernhard and Felder, Stefan and Mulligan, Sean and Oertel, Mario and Palermo, Michele}, title = {Hydraulic structures engineering: An evolving science in a changing world}, series = {Wires Water}, volume = {8}, journal = {Wires Water}, number = {2}, publisher = {Wiley}, address = {Weinheim}, issn = {2049-1948}, doi = {10.1002/wat2.1505}, year = {2021}, language = {en} } @inproceedings{BlankeSchmidtGoettscheetal.2022, author = {Blanke, Tobias and Schmidt, Katharina S. and G{\"o}ttsche, Joachim and D{\"o}ring, Bernd and Frisch, J{\´e}r{\^o}me and van Treeck, Christoph}, title = {Time series aggregation for energy system design: review and extension of modelling seasonal storages}, series = {Energy Informatics}, volume = {5}, booktitle = {Energy Informatics}, number = {1, Article number: 17}, editor = {Weidlich, Anke and Neumann, Dirk and Gust, Gunther and Staudt, Philipp and Sch{\"a}fer, Mirko}, publisher = {Springer Nature}, issn = {2520-8942}, doi = {10.1186/s42162-022-00208-5}, pages = {14 Seiten}, year = {2022}, abstract = {Using optimization to design a renewable energy system has become a computationally demanding task as the high temporal fluctuations of demand and supply arise within the considered time series. The aggregation of typical operation periods has become a popular method to reduce effort. These operation periods are modelled independently and cannot interact in most cases. Consequently, seasonal storage is not reproducible. This inability can lead to a significant error, especially for energy systems with a high share of fluctuating renewable energy. The previous paper, "Time series aggregation for energy system design: Modeling seasonal storage", has developed a seasonal storage model to address this issue. Simultaneously, the paper "Optimal design of multi-energy systems with seasonal storage" has developed a different approach. This paper aims to review these models and extend the first model. The extension is a mathematical reformulation to decrease the number of variables and constraints. Furthermore, it aims to reduce the calculation time while achieving the same results.}, language = {en} } @incollection{GrossHeckenRenz1999, author = {Groß, Rolf Fritz and Hecken, M. and Renz, Ulrich}, title = {Hot gas filtration with ceramic filter candles: experimental and numerical investigations on fluid flow during element cleaning}, series = {High temperature gas cleaning. Vol. 2}, booktitle = {High temperature gas cleaning. Vol. 2}, editor = {Dittler, A. and Hemmer, G. and Kasper, G.}, publisher = {KIT Institut f{\"u}r Mechanische Verfahrenstechnik und Mechanik}, address = {Karlsruhe}, isbn = {3-9805220-1-6}, pages = {862 -- 873}, year = {1999}, abstract = {Ceramic hot gas filters are widely used in combined cycles based on pressurised fluidised beds. They fulfil most of the demands with respect to cleaning efficiency and long time durability, but their operation regarding the consumption of pulse gas and energy still has to be optimised. Experimental investigations were carried out to measure the flow field, the pressure and the gas temperature inside the filter candle during pulse jet cleaning. These results are compared with the results of a numerical procedure based on a solution of the two - dimensional conservation equations for momentum and energy. The observed difficulties handling different flow regimes like highly turbulent flow as well as Darcy flow simultaneously are discussed.}, language = {en} } @article{CheenakulaPaulsenOttetal.2023, author = {Cheenakula, Dheeraja and Paulsen, Svea and Ott, Fabian and Gr{\"o}mping, Markus}, title = {Operational window of a deammonifying sludge for mainstream application in a municipal wastewater treatment plant}, series = {Water and Environment Journal}, volume = {38}, journal = {Water and Environment Journal}, number = {1}, publisher = {Wiley}, address = {Chichester}, issn = {1747-6593}, doi = {10.1111/wej.12898}, pages = {59 -- 70}, year = {2023}, abstract = {The present work aimed to study the mainstream feasibility of the deammonifying sludge of side stream of municipal wastewater treatment plant (MWWTP) in Kaster, Germany. For this purpose, the deammonifying sludge available at the side stream was investigated for nitrogen (N) removal with respect to the operational factors temperature (15-30°C), pH value (6.0-8.0) and chemical oxygen demand (COD)/N ratio (≤1.5-6.0). The highest and lowest N-removal rates of 0.13 and 0.045 kg/(m³ d) are achieved at 30 and 15°C, respectively. Different conditions of pH and COD/N ratios in the SBRs of Partial nitritation/anammox (PN/A) significantly influenced both the metabolic processes and associated N-removal rates. The scientific insights gained from the current work signifies the possibility of mainstream PN/A at WWTPs. The current study forms a solid basis of operational window for the upcoming semi-technical trails to be conducted prior to the full-scale mainstream PN/A at WWTP Kaster and WWTPs globally.}, language = {en} } @article{CheenakulaGriebelMontagetal.2023, author = {Cheenakula, Dheeraja and Griebel, Kai and Montag, David and Gr{\"o}mping, Markus}, title = {Concept development of a mainstream deammonification and comparison with conventional process in terms of energy, performance and economical construction perspectives}, series = {Frontiers in Microbiology}, volume = {14}, journal = {Frontiers in Microbiology}, number = {11155235}, editor = {Huang, Xiaowu}, publisher = {Frontiers}, issn = {1664-302X}, doi = {10.3389/fmicb.2023.1155235}, pages = {1 -- 15}, year = {2023}, abstract = {Deammonification for nitrogen removal in municipal wastewater in temperate and cold climate zones is currently limited to the side stream of municipal wastewater treatment plants (MWWTP). This study developed a conceptual model of a mainstream deammonification plant, designed for 30,000 P.E., considering possible solutions corresponding to the challenging mainstream conditions in Germany. In addition, the energy-saving potential, nitrogen elimination performance and construction-related costs of mainstream deammonification were compared to a conventional plant model, having a single-stage activated sludge process with upstream denitrification. The results revealed that an additional treatment step by combining chemical precipitation and ultra-fine screening is advantageous prior the mainstream deammonification. Hereby chemical oxygen demand (COD) can be reduced by 80\% so that the COD:N ratio can be reduced from 12 to 2.5. Laboratory experiments testing mainstream conditions of temperature (8-20°C), pH (6-9) and COD:N ratio (1-6) showed an achievable volumetric nitrogen removal rate (VNRR) of at least 50 gN/(m3∙d) for various deammonifying sludges from side stream deammonification systems in the state of North Rhine-Westphalia, Germany, where m3 denotes reactor volume. Assuming a retained Norganic content of 0.0035 kgNorg./(P.E.∙d) from the daily loads of N at carbon removal stage and a VNRR of 50 gN/(m3∙d) under mainstream conditions, a resident-specific reactor volume of 0.115 m3/(P.E.) is required for mainstream deammonification. This is in the same order of magnitude as the conventional activated sludge process, i.e., 0.173 m3/(P.E.) for an MWWTP of size class of 4. The conventional plant model yielded a total specific electricity demand of 35 kWh/(P.E.∙a) for the operation of the whole MWWTP and an energy recovery potential of 15.8 kWh/(P.E.∙a) through anaerobic digestion. In contrast, the developed mainstream deammonification model plant would require only a 21.5 kWh/(P.E.∙a) energy demand and result in 24 kWh/(P.E.∙a) energy recovery potential, enabling the mainstream deammonification model plant to be self-sufficient. The retrofitting costs for the implementation of mainstream deammonification in existing conventional MWWTPs are nearly negligible as the existing units like activated sludge reactors, aerators and monitoring technology are reusable. However, the mainstream deammonification must meet the performance requirement of VNRR of about 50 gN/(m3∙d) in this case.}, language = {en} } @article{BungErpicumTullis2020, author = {Bung, Daniel Bernhard and Erpicum, S{\´e}bastien and Tullis, Blanke P.}, title = {Advances in hydraulic structures engineering}, series = {Journal of Hydraulic Engineering}, volume = {147}, journal = {Journal of Hydraulic Engineering}, number = {1}, publisher = {ASCE}, address = {Reston, Va.}, issn = {0733-9429 (Druckausgabe)}, doi = {10.1061/(ASCE)HY.1943-7900.0001851}, pages = {1 Seite}, year = {2020}, language = {en} } @article{vonHaefenKrautwaldStolleetal.2022, author = {von H{\"a}fen, Hajo and Krautwald, Clemens and Stolle, Jacob and Bung, Daniel Bernhard and Goseberg, Nils}, title = {Overland flow of broken solitary waves over a two-dimensional coastal plane}, series = {Coastal Engineering}, volume = {175}, journal = {Coastal Engineering}, number = {August}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1872-7379}, doi = {10.1016/j.coastaleng.2022.104125}, pages = {14 Seiten}, year = {2022}, abstract = {Landslides, rock falls or related subaerial and subaqueous mass slides can generate devastating impulse waves in adjacent waterbodies. Such waves can occur in lakes and fjords, or due to glacier calving in bays or at steep ocean coastlines. Infrastructure and residential houses along coastlines of those waterbodies are often situated on low elevation terrain, and are potentially at risk from inundation. Impulse waves, running up a uniform slope and generating an overland flow over an initially dry adjacent horizontal plane, represent a frequently found scenario, which needs to be better understood for disaster planning and mitigation. This study presents a novel set of large-scale flume test focusing on solitary waves propagating over a 1:14.5 slope and breaking onto a horizontal section. Examining the characteristics of overland flow, this study gives, for the first time, insight into the fundamental process of overland flow of a broken solitary wave: its shape and celerity, as well as its momentum when wave breaking has taken place beforehand.}, language = {en} } @article{Bung2021, author = {Bung, Daniel Bernhard}, title = {Extreme flooding in Western Germany: some thoughts on hazards, return periods and risk}, series = {Hydrolink}, journal = {Hydrolink}, number = {4}, publisher = {International Association for Hydro-Environment Engineering and Research (IAHR)}, address = {Madrid}, pages = {108 -- 113}, year = {2021}, abstract = {The low-pressure system Bernd involved extreme rainfalls in the Western part of Germany in July 2021, resulting in major floods, severe damages and a tremendous number of casualties. Such extreme events are rare and full flood protection can never be ensured with reasonable financial means. But still, this event must be starting point to reconsider current design concepts. This article aims at sharing some thoughts on potential hazards, the selection of return periods and remaining risk with the focus on Germany.}, language = {en} } @phdthesis{Bung2023, author = {Bung, Daniel Bernhard}, title = {Imaging techniques for investigation of free-surface flows in hydraulic laboratories}, doi = {10.25926/BUW/0-172}, pages = {XXIII, 218 Seiten}, year = {2023}, abstract = {This thesis aims at the presentation and discussion of well-accepted and new imaging techniques applied to different types of flow in common hydraulic engineering environments. All studies are conducted in laboratory conditions and focus on flow depth and velocity measurements. Investigated flows cover a wide range of complexity, e.g. propagation of waves, dam-break flows, slightly and fully aerated spillway flows as well as highly turbulent hydraulic jumps. Newimagingmethods are compared to different types of sensorswhich are frequently employed in contemporary laboratory studies. This classical instrumentation as well as the general concept of hydraulic modeling is introduced to give an overview on experimental methods. Flow depths are commonly measured by means of ultrasonic sensors, also known as acoustic displacement sensors. These sensors may provide accurate data with high sample rates in case of simple flow conditions, e.g. low-turbulent clear water flows. However, with increasing turbulence, higher uncertainty must be considered. Moreover, ultrasonic sensors can provide point data only, while the relatively large acoustic beam footprint may lead to another source of uncertainty in case of relatively short, highly turbulent surface fluctuations (ripples) or free-surface air-water flows. Analysis of turbulent length and time scales of surface fluctuations from point measurements is also difficult. Imaging techniques with different dimensionality, however, may close this gap. It is shown in this thesis that edge detection methods (known from computer vision) may be used for two-dimensional free-surface extraction (i.e. from images taken through transparant sidewalls in laboratory flumes). Another opportunity in hydraulic laboratory studies comes with the application of stereo vision. Low-cost RGB-D sensors can be used to gather instantaneous, three-dimensional free-surface elevations, even in flows with very high complexity (e.g. aerated hydraulic jumps). It will be shown that the uncertainty of these methods is of similar order as for classical instruments. Particle Image Velocimetry (PIV) is a well-accepted and widespread imaging technique for velocity determination in laboratory conditions. In combination with high-speed cameras, PIV can give time-resolved velocity fields in 2D/3D or even as volumetric flow fields. PIV is based on a cross-correlation technique applied to small subimages of seeded flows. The minimum size of these subimages defines the maximum spatial resolution of resulting velocity fields. A derivative of PIV for aerated flows is also available, i.e. the so-called Bubble Image Velocimetry (BIV). This thesis emphasizes the capacities and limitations of both methods, using relatively simple setups with halogen and LED illuminations. It will be demonstrated that PIV/BIV images may also be processed by means of Optical Flow (OF) techniques. OF is another method originating from the computer vision discipline, based on the assumption of image brightness conservation within a sequence of images. The Horn-Schunck approach, which has been first employed to hydraulic engineering problems in the studies presented herein, yields dense velocity fields, i.e. pixelwise velocity data. As discussed hereinafter, the accuracy of OF competes well with PIV for clear-water flows and even improves results (compared to BIV) for aerated flow conditions. In order to independently benchmark the OF approach, synthetic images with defined turbulence intensitiy are used. Computer vision offers new opportunities that may help to improve the understanding of fluid mechanics and fluid-structure interactions in laboratory investigations. In prototype environments, it can be employed for obstacle detection (e.g. identification of potential fish migration corridors) and recognition (e.g. fish species for monitoring in a fishway) or surface reconstruction (e.g. inspection of hydraulic structures). It can thus be expected that applications to hydraulic engineering problems will develop rapidly in near future. Current methods have not been developed for fluids in motion. Systematic future developments are needed to improve the results in such difficult conditions.}, language = {en} } @inproceedings{LangohrBungCrookston2022, author = {Langohr, Philipp and Bung, Daniel Bernhard and Crookston, Brian M.}, title = {Hybrid investigation of labyrinth weirs: Discharge capacity and energy dissipation}, series = {Proceedings of the 39th IAHR World Congress}, booktitle = {Proceedings of the 39th IAHR World Congress}, editor = {Ortega-S{\´a}nchez, Miguel}, publisher = {International Association for Hydro-Environment Engineering and Research (IAHR)}, address = {Madrid}, isbn = {978-90-832612-1-8}, issn = {2521-7119 (print)}, doi = {10.3850/IAHR-39WC252171192022738}, pages = {2313 -- 2318}, year = {2022}, abstract = {The replacement of existing spillway crests or gates with labyrinth weirs is a proven techno-economical means to increase the discharge capacity when rehabilitating existing structures. However, additional information is needed regarding energy dissipation of such weirs, since due to the folded weir crest, a three-dimensional flow field is generated, yielding more complex overflow and energy dissipation processes. In this study, CFD simulations of labyrinth weirs were conducted 1) to analyze the discharge coefficients for different discharges to compare the Cd values to literature data and 2) to analyze and improve energy dissipation downstream of the structure. All tests were performed for a structure at laboratory scale with a height of approx. P = 30.5 cm, a ratio of the total crest length to the total width of 4.7, a sidewall angle of 10° and a quarter-round weir crest shape. Tested headwater ratios were 0.089 ≤ HT/P ≤ 0.817. For numerical simulations, FLOW-3D Hydro was employed, solving the RANS equations with use of finite-volume method and RNG k-ε turbulence closure. In terms of discharge capacity, results were compared to data from physical model tests performed at the Utah Water Research Laboratory (Utah State University), emphasizing higher discharge coefficients from CFD than from the physical model. For upstream heads, some discrepancy in the range of ± 1 cm between literature, CFD and physical model tests was identified with a discussion regarding differences included in the manuscript. For downstream energy dissipation, variable tailwater depths were considered to analyze the formation and sweep-out of a hydraulic jump. It was found that even for high discharges, relatively low downstream Froude numbers were obtained due to high energy dissipation involved by the three-dimensional flow between the sidewalls. The effects of some additional energy dissipation devices, e.g. baffle blocks or end sills, were also analyzed. End sills were found to be non-effective. However, baffle blocks with different locations may improve energy dissipation downstream of labyrinth weirs.}, language = {en} } @inproceedings{CrookstonBung2022, author = {Crookston, Brian M. and Bung, Daniel Bernhard}, title = {Application of RGB-D cameras in hydraulic laboratory studies}, series = {Proceedings of the 39th IAHR World Congress}, booktitle = {Proceedings of the 39th IAHR World Congress}, editor = {Ortega-S{\´a}nchez, Miguel}, publisher = {International Association for Hydro-Environment Engineering and Research (IAHR)}, address = {Madrid}, isbn = {978-90-832612-1-8}, issn = {2521-7119 (print)}, doi = {10.3850/IAHR-39WC252171192022964}, pages = {5127 -- 5133}, year = {2022}, abstract = {Non-intrusive measuring techniques have attained a lot of interest in relation to both hydraulic modeling and prototype applications. Complimenting acoustic techniques, significant progress has been made for the development of new optical methods. Computer vision techniques can help to extract new information, e. g. high-resolution velocity and depth data, from videos captured with relatively inexpensive, consumer-grade cameras. Depth cameras are sensors providing information on the distance between the camera and observed features. Currently, sensors with different working principles are available. Stereoscopic systems reference physical image features (passive system) from two perspectives; in order to enhance the number of features and improve the results, a sensor may also estimate the disparity from a detected light to its original projection (active stereo system). In the current study, the RGB-D camera Intel RealSense D435, working on such stereo vision principle, is used in different, typical hydraulic modeling applications. All tests have been conducted at the Utah Water Research Laboratory. This paper will demonstrate the performance and limitations of the RGB-D sensor, installed as a single camera and as camera arrays, applied to 1) detect the free surface for highly turbulent, aerated hydraulic jumps, for free-falling jets and for an energy dissipation basin downstream of a labyrinth weir and 2) to monitor local scours upstream and downstream of a Piano Key Weir. It is intended to share the authors' experiences with respect to camera settings, calibration, lightning conditions and other requirements in order to promote this useful, easily accessible device. Results will be compared to data from classical instrumentation and the literature. It will be shown that even in difficult application, e. g. the detection of a highly turbulent, fluctuating free-surface, the RGB-D sensor may yield similar accuracy as classical, intrusive probes.}, language = {en} }