267 research outputs found
Scripts for: Conjunctive use of mineralogy and elemental composition for empirical forensic provenancing of topsoil from Canberra, Australia
No full textThis data was used in the preparation of FORC-D-23-00035 "Conjunctive use of mineralogy and elemental composition for empirical forensic provenancing of topsoil from Canberra, Australia".Authors: Michael G. Aberle 1, Ulrike Troitzsch 2, James Robertson 1, Jurian A. Hoogewerff 11) National Centre for Forensic Studies, University of Canberra, Australia, 2) Research School of Earth Sciences, Australian National University, Australia, Corresponding author: Michael Aberle: email: [email protected] data and script provided are experimental and the authors are not liable for any misuse or unexpected outcomes of the data and scripts for legal applications or otherwise
The effect of bed porosity on turbulent flow in gravel-bed rivers
No full textThis thesis presents the main findings from laboratory experiments that were specially designed to study the effect of gravel bed porosity on the surface flow characteristics. The thesis also contains five primary and two secondary research papers in which the results are discussed in detail.
In order to study the effect of porosity on flow resistance and near-bed turbulence, a non-porous counterpart of a water-worked gravel-bed surface was produced using a casting technique. The casting technique was also used to study the influence of gravel grain orientation on bulk flow resistance. The accuracy of the casting technique was evaluated, and the results indicated that the cast replicated the original surface accurately. The vertical distribution of porosity in the water-worked gravel-bed was also investigated. Hydraulic measurements were performed over three different bed types: water-worked gravel-bed, cast-bed and rotated cast-bed (cast tiles were rotated 180 degrees). The rotated cast-bed imposed larger flow resistance on the flow, thus the grain orientation played an important role determining the flow resistance. Moreover, differences in flow resistance and turbulence characteristics between porous water-worked gravel-bed and non-porous cast-bed are discussed. The porous water-worked gravel-bed imposed slightly larger resistance on the flow than the non-porous cast-bed. The analysis of turbulence flow characteristics between water-worked gravel-bed and cast-bed revealed that a higher momentum flux occurred over the water-worked gravel-bed. Moreover, the form-induced stresses were higher over the cast-bed than over the gravel-bed. This was associated with a strong recirculation of the fluid over the cast-bed as fluid cannot infiltrate. In contrast, fluid can infiltrate into the subsurface of the water-worked gravel-bed, causing less recirculation in the water-sediment interface
Bed shear stress measurements in rough beds flows through sparse array of rigid emergent vegetation
No full textThis dataset provides the hydraulic boundary conditions, bed shear stress measurements, and double-averaged velocity measurements collected in flume experiments presented in the article "Bed shear stress model for rough bed flows through rigid emergent vegetation" (Aliaga & Aberle, 2025). This research characterizes bed shear stress and double-averaged flow characteristics in rough-bed flows covered with sparse arrays of rigid emergent cylinders. For this purpose, a novel adaptation of a shear plate was used to directly measure the bed shear stress acting at the canopy scale. These bed shear stress measurements were analyzed in relation to spatially averaged near-bed flow quantities for two array densities and a reference scenario without cylinders. The primary outcome of this research is the formulation of a bed shear stress model for rough-bed flows covered with rigid emergent vegetation
Bed shear stress and near-bed flow through sparse arrays of rigid emergent vegetation
No full textThis data set provides the hydraulic boundary conditions, bed shear stress measurements, and near-bed flow field velocity measurements collected in flume experiments presented in the article "Bed Shear Stress and Near-bed Flow through Sparse Arrays of Rigid Emergent Vegetation" (Aliaga & Aberle, 2024). This research explores bed shear stress and near-bed flow characteristics in sparse arrays of rigid emergent cylinders mimicking vegetation. For this purpose, a novel adaptation of a shear plate was used to directly measure the bed shear stress acting at the canopy scale. These bed shear stress measurements were analyzed in relation to spatially averaged near-bed flow quantities for different array densities
Riprap design on the downstream slopes of rockfill dams
No full textSammendrag:
Erosjonssikring av stein er mye brukt, blant annet for å sikre nedstrøms skråning på steinfyllingsdammer mot erosjon fra ulykkeslaster som overtopping eller gjennomstrømning. Denne avhandlingen fokuserer på stabiliteten og utformingen av erosjonssikring av stein lagt som rauset steinsikring eller plastring. Plastring ble bygd ved å sette stein i forband med god innbyrdes kontakt og med lengste akse hellende mot skråningen. Forsøkene ble utført på en skråning på 1:1,5 (vertikalt: horisontalt). Plastringsparametere, bruddmekanismer, hydrauliske parametere og eksisterende stabilitetsanalyser ble undersøkt for å optimalisere utforming av rauset steinsikring og plastring på bratte skråninger. Stabiliteten til erosionssikringen ble undersøkt med fysiske modellforsøk i ulike målestokk og uttrykt gjennom det kritiske steinbaserte Froudetallet.
For å kvantifisere kreftene som virker på en spesifisk stein, ble det nylig utviklete måleutstyret ’Smartstone’ testet. En Smartstone sonde ble montert i en plastringsstein for å måle akselerasjonen i øyeblikket når steinen ble erodert fra plastringen. Den aktuelle versjonen av Smartstone må imiderltid bli videre utviklet for å tillate den ønskede anvendelsen.
Fysiske modellforsøk og feltforsøk med storskala plastringsstein ble utført for å undersøke stabiliteten til rauset steinsikring og plastring. Felt- og modellforsøkene med rauset steinsikring viste god overensstemmelse i forhold til stabilitet, pakningstetthet og det visuelt observerte strømningsmønsteret. Forsøkene utført med plastring hadde bra overensstemmelse mellom felt og modell i forhold til strømningsmønster og overtoppingshøyde. Plastringene i modellforsøkene var imidlertid tettere pakket og mer stabile enn i felt. Forskyvinger i plastringslaget ble målt i modellforsøkene. Forskyvingene førte til en glipe i overgangen mellom den horisontale kronen og skråningen. Plastringen ble ustabil når glipen hadde blitt større enn omtrent en steinlengde. Akkumulerende forskyvinger ble dermed identifisert som bruddmekanisme for plastring på bratte skråninger. Siden forskyvingene utviklet seg gradvis, anbefales det å inkludere tidsdimensjonen i stabilitetsanalyser i tillegg til vannføring. Plastring hadde i gjennomsnitt sju ganger større kritisk steinrelatert Froudetall enn rauset steinsikring. Imidlertid kan rauset steinsikring være stabil nok for noen bruksområder, og plastring bør bare bli vurdert hvis økt stabilitet er nødvendig. For å oppnå optimal utforming av erosjonssikring av stein, må kravene til type erosjonssikring, steinstørrelse og plastringstetthet, samt de tilhørende konstnadene, avveises mot det ønskete stabilitetsnivået.Zusammenfassung:
Deckwerke aus Steinen sind eine weitverbreitete Massnahme gegen Erosion. Sie werden unter anderem auf den luftseitigen Hängen von Staudämmen erstellt, um diese in ausserordentlichen Lastfällen wie Über- oder Durchströmen vor Erosion zu schützen. Die vorliegende Dissertation fokussiert auf die Stabilität solcher Deckwerke, die entweder als Blockwurf oder Blocksatz ausgeführt werden. Bei einem Blockwurf werden die Steine willkürlich verteilt. Ein Blocksatz hingegen besteht aus Steinen, die ineinandergreifend gesetzt werden. Die Steine können zusätzlich mit ihrer längsten Achse gegen den Hang geneigt platziert werden. Für die Versuche hatten die Hänge ein Gefälle von 1:1.5 (horizontal: vertikal). Die Parameter von Deckwerken aus Steinen, Fehlermechanismen, hydraulische Parameter und bestehenden Stabilitätsanalysen wurden untersucht, um die Bauweise der Deckwerke zu optimieren. Die Deckwerksstabilität wurde mit Modellversuchen in verschiedenen Massstäben ermittelt und durch die kritische steinbezogene Froude-Zahl ausgedrückt.
Um die Kräfte, die auf einen spezifischen Stein wirken, zu messen, wurde das neulich entwickelt ’Smartstone’ Messgerät getestet. Eine Smartstonesonde wurde in einen Stein eingebaut werden, um die Beschleunigung zu messen, wenn der Stein aus dem Deckwerk erodiert wird. Die aktuelle Version der Smartstones muss jedoch weiterentwickelt werden, um die gewünschte Anwendung zuzulassen.
Physische Modellversuche und Feldversuche mit grossmassstäblichen Steinen wurden durchgeführt, um die Deckwerksstabilität zu untersuchen. Die Stabilität, Setzungsdichte und die visuell beobachteten Strömungsverhältnisse stimmten für Blockwurf zwischen den Feld- und Modellversuchen überein. Die Strömungsverhältnisse und die Überströmungswassertiefe waren für Blocksatz in den Feld- und Modellversuchen ähnlich. Die Blocksätze im Modell waren jedoch dichter gesetzt und stabiler. In den Modellversuchen wurden die Verschiebungen von ausgewählten Steinen im Deckwerk gemessen. Die Verschiebungen führten zu einer Lücke im Übergang von der Dammkrone zum luftseitigen Hang. Der Blocksatz wurde unstabil, als die Lücke die Grösse einer Steinlänge überstieg. Folglich wurden Verschiebungen als Fehlermechanismus für Blocksätze auf steilen Hängen identifiziert. Da die Verschiebungen sukzessive anwuchsen, sollte die zeitliche Dimension in Stabilitätsuntersuchungen zusätzlich zum Abfluss berücksichtigt werden. Die kritische steinbezogene Froude-Zahl war für Blocksatz im Durchschnitt siebenmal höher als die von Blockwurf. Jedoch kann die Stabilität von Blockwurf für gewisse Anwendungen ausreichen und Blocksatz sollte nur in Betracht gezogen werden, falls eine erhöhte Stabilität erforderlich ist. Um die Bauweise von Steindeckwerken zu optimieren, müssen die Anforderungen wie Art des Deckwerks, Steingrösse und Setzungsdichte im Deckwerk sowohl als auch die damit verbundenen Kosten bezüglich dem gewünschten Stabilitätsniveau abgewogen werden. Froude-Zahl war für Blocksatz im Durchschnitt siebenmal höher als die von Blockwurf. Jedoch kann die Stabilität von Blockwurf für gewisse Anwendungen ausreichen und Blocksatz sollte nur in Betracht gezogen werden, falls eine erhöhte Stabilität erforderlich ist. Um die Bauweise von Steindeckwerken zu optimieren, müssen die Anforderungen wie Art des Deckwerks, Steingrösse und Setzungsdichte im Deckwerk sowohl als auch die damit verbundenen Kosten bezüglich dem gewünschten Stabilitätsniveau abgewogen werden.Abstract:
Riprap is widely used as erosion protection. To prevent erosion in case of accidental overtopping or trough flow, the downstream slopes of rockfill dams can be secured with riprap. The present thesis focuses on the stability and design of dumped and placed riprap made of natural stone. Placed riprap for the tests was constructed by setting stones in an interlocking pattern, with their longest axes inclined towards a slope of 1:1.5 (vertical: horizontal). Riprap parameters, failure mechanisms, hydraulic parameters and existing stability approaches were addressed to optimize riprap design on steep slopes. Riprap stability was investigated with physical model tests in different scales and was expressed through the critical stone-related Froude number.
In order to quantify the forces acting on a specific stone, the novel ’Smartstone’ monitoring equipment was tested. A Smartstone probe was mounted in a riprap stone to measure the acceleration in the moment when the stone was eroded from the riprap. However, the current version of the Smartstone equipment needs further development to allow for the desired application.
Physical model tests and field tests with large-scale riprap stones were carried out to investigate riprap stability. For dumped riprap, similarity was found between the field and model tests in terms of riprap stability, packing density and visually observed flow pattern. The model tests and field tests with placed riprap showed good agreement with regard to flow pattern and overtopping height. However, the placed ripraps in the model had a higher packing density and were more stable. Displacements within the riprap layer were monitored during the model tests. The displacements lead to a gap at the transition between the horizontal crest and the downstream slope. The riprap became unstable when the gap exceeded approximately one stone length. Accumulating displacements were hence identified as failure mechanism for placed riprap on steep slopes. Due to the gradual development of the displacements, the dimension of time is recommended to be included in stability analyses in addition to discharge. Placed riprap had on average a seven times higher critical stone-related Froude number than dumped riprap. However, dumped riprap might provide sufficient stability for certain applications, and placed riprap should just be considered if increased stability is required. For an optimized riprap design, the requirements about riprap type, stone size and packing density as well as the corresponding costs have to be balanced with the desired level of stability
Scripts for: Conjunctive use of mineralogy and elemental composition for empirical forensic provenancing of topsoil from Canberra, Australia
No full textThis data was used in the preparation of FORC-D-23-00035 "Conjunctive use of mineralogy and elemental composition for empirical forensic provenancing of topsoil from Canberra, Australia".Authors: Michael G. Aberle 1, Ulrike Troitzsch 2, James Robertson 1, Jurian A. Hoogewerff 11) National Centre for Forensic Studies, University of Canberra, Australia, 2) Research School of Earth Sciences, Australian National University, Australia, Corresponding author: Michael Aberle: email: [email protected] data and script provided are experimental and the authors are not liable for any misuse or unexpected outcomes of the data and scripts for legal applications or otherwise.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV
Acoustic Instruments for Mean Flow Characterization in Field Conditions: Acoustic Doppler Current Profilers (ADCP)
No full textThis two-volume book is a comprehensive guide to designing, conducting and interpreting experiments in a broad range of topics associated with hydraulic engineering. It is the first substantial effort in hydraulic engineering to assemble in one place descriptions of all the components of experimentation along with a concise outline of essential theory to highlight the intrinsic connection between analytical and experimental research and illustrate the need for their complementary use. Providing end-to-end guidance to support experimentalists is long overdue, as most of the information can only be found in scientific papers or specialized monographs on laboratory and fieldwork practice. The book was prepared for college faculty, researchers, practitioners, and students involved in hydraulics experiments. Written by a team of more than 45 authors well-experienced in hydraulics experimentation, the book takes into account experiments performed under a range of conditions, including well-equipped and -staffed laboratories, and laboratories lacking aspects of advanced instrumentation and expertise. The book could serve as a textbook on hydraulics experiments. Its style is intentionally concise and makes frequent use of convenient summaries, tables and figures to present information. The writers provide specific guidance on methods and instruments currently used in hydraulics experiments, and emphasizes new and emerging measurement technologies and analysis methods. Extensive references enable interested readers to further explore details on each topic. Although the book focuses primarily on laboratory experiments, including hydraulic modelling, it also applies to fieldwork of varying complexity and accessibility.Fil: Szupiany, Ricardo Nicolas. Universidad Nacional del Litoral. Facultad de Ingeniería y Ciencias Hídricas. Departamento de Hidráulica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Garcia, Carlos M.. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Estudios Tecnológicos Sobre el Agua; ArgentinaFil: Oberg, Kevin. United States Geological Survey; Estados Unido
Plant patch hydrodynamics in streams : Mean flow, turbulence, and drag forces
No full textPeer reviewe
Hydrologic and metal removal potential of filtering swales for stormwater control in cold climates
No full textRunoff from urban areas carries a wide range of pollutants both particle-bound and dissolved. Dissolved pollutants are generally more mobile and bioavailable as well as more difficult to remove by conventional infiltration based systems. Three adsorbent amended filters were studied for suitability in filtering swales for stormwater runoff management in cold climates, with special attention to the capture of dissolved metals. These alternative filters were composed of clean homogeneous sand and one adsorbent. The adsorbents used along the course of this thesis were granulated activated charcoal, granulated olivine Blueguard® G1-3, and pine bark Pinus Sylvestris. These adsorbents were selected in a previous multi-criteria study in which factors such as sorption capacity with respect to dissolved zinc (Zn), copper (Cu), nickel (Ni), and lead (Pb), cost,availability, end-of-life disposal, and others were considered.
The investigations were divided into the following 4 parts
1. An urban runoff sampling campaign over the course of 17 months in the city of Trondheim in order to characterize runoff and understand local patterns.
2. A column test to study the retention performance of these filters towards toxic metals detrimental for receiving water bodies.
3. A column test to study the infiltration response of these filters under cold climate conditions.
4. A full scale experimental study with two swales composed of selected filters and one swale composed of traditional soil for bioinfiltration in order to explore and compare their hydrological balance during runoff events.
The results from the characterization of urban runoff showed strong seasonal and spatial variations in all studied parameters. Metals associated to colloids were practically nonexistent, and Cu was the only studied metal that exceeded Norwegian, European, and American water quality standards for fresh water bodies. Overall the metals were mostly particle-bound (> 99 % for Pb, > 96% for Ni, > 90 % for Cu, and > 91 % for Ni), and this trend was followed over the course of the year. Lack of cleaning and maintenance in low annual average daily traffic streets can yield pollutant concentration similar as transited roads. In addition, boundaries associated to cold climate such as use of studded tires, deicing salts, and low temperatures were more likely reasons for the seasonal variations rather than long accumulation times on snow piles.
With regard to the retention performance of the filters, pine bark and olivine amended filter showed the best affinity to the target metals both under high inflow rates (> 97 % retention) and large inflow volumes (no exhaustion was reached in these filters), which helped to decide the candidate filters to test in full scale. In addition, all filters except the charcoal amended filter for Ni showed little leaching of metals (< 2.8 %) after the addition of sodium chloride (NaCl), being a common de-icing salt to avoid snow accumulation on roads. The pine bark amended filter showed the longest estimated service life, which will vary according to the target metal as well as the size of the tributary. For example, a filter composed of sand and pine bark receiving polluted runoff from a tributary 50 times larger (than the filter) is expected to last 9, 13 and 46 years for Zn, Cu and Ni, respectively.
With respect to infiltration capacity under cold climate conditions, snowmelt runoff will take more than 21 hours to be infiltrated through a partially frozen filter. This means that a ponding capacity is required if “shock” pollutant loads from snowmelt must be captured in the system. However, after the first 24 hours from the observation of the first discharge, infiltration rates will be higher than 1.27 cm/h, a value typically recommended for bioinfiltration. In addition, some of the studied adsorbents showed high unfrozen water content as well as being highly porous. These properties make the infiltration response to negative temperatures better due to positive impacts on the ratio ice content / porosity as well as on the heat exchange between incoming runoff and ice in the filter media.
In the swale setup, two swales composed of adsorbent amended filters (filtering swales) were compared with a traditional grass swale, and among each other. The experiments were performed under different boundary conditions that have been shown to influence the hydrological balance; type of media (olivine amended filter, pine bark amended filter, and soil traditionally used for bioinfiltration practices), inflow rate, swale slope, and degree of saturation of the media. Results showed that the infiltration performance of the filtering swales was considerably better and only dependent on the inflow rate for the studied range of slopes, up to 4 %. An equation that relates infiltration performance, storm intensity, and size of the drainage area is included to help planners to design filtering swales presented in this thesis. As an example, these swales can capture 90% of the runoff generated by a tributary 40 times larger (than the swale) during a storm event with a peak intensity of 12.2 mm/h.
All in all, the results of this thesis show that the environmental and hydrological benefits provided by the adsorbent amended filters are promising for further field implementation in cold climates. However, this thesis has not considered any economic feasibility aspects, which would be of interest for an overall assessment.Digital full text not availabl
Parametrisation of aquatic vegetation in hydraulic and coastal research: The importance of plant biomechanics in the hydrodynamics of vegetated flows
No full textUnderstanding the complexity of the interactions between aquatic biological systems and their physical environment is a critical condition for the sustainable management of aquatic environments. In such ecosystems, aquatic vegetation holds a central place by influencing flow and turbulent processes, thus playing a major role both from an engineering and ecological point of view. However, the characterisation of the hydrodynamics of vegetated flows is facing several issues due to the complexity of the plant-flow interactions. In such a complex system, the plant's biomechanical properties are a key parameter governing the interplay between the living organism and its physical environment: a variation of the plant’s mechanics in time or space will generally imply changes in these regulation processes, which in turn can lead to major changes in the physical/ecological environment. The consideration of mechanical interactions, however, is fairly new to engineers, biologists and ecologists, as it defines an interface between engineering and ecology. As a consequence, this area of research has remained mostly unexplored and a lot of processes are to be discovered at the edge of the different disciplines.
This thesis deepened the level of the understanding of plant-flow mechanical interactions and of the plant structural properties, in order to improve the parametrisation of aquatic vegetation in hydraulic and coastal research. Measurement techniques and experimental protocols were developed to collect plant biomechanical properties and a methodology for the collection of such data was provided based on the flexibility of the plant elements. New methods to design plant surrogates for hydraulic experimentation were further investigated based on mechanical similarity. In parallel, this thesis reviewed the measurement techniques commonly used to measure drag forces on submerged plants, and developed a theoretical framework to estimate random wave and random wave-plus-current induced drag forces on submerged plants. This framework is based on the definition of a drag coefficient for a given type of plant. Moreover, the common drag coefficient formulations were discussed, identifying possibilities for a standardisation of the formulations for oscillatory and steady flows. Finally, in order to understand the effects of the development of a biological community at an interface fluid/solid, the example of marine biofouling was investigated through flow visualisation. The methodologies developed in this thesis are to be used in ongoing projects and will trigger new research activities at NTNU and elsewhere
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