Matthias Bürgler

Last Name

Bürgler

First Name

Matthias

ORCID

0000-0001-6683-2123

Organisational unit

03820 - Boes, Robert / Boes, Robert

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Publications 1 - 10 of 18

Integrated hazard assessment of lake tsunamis triggered by subaqueous and subaerial landslides
Strupler, Michael; Bürgler, Matthias; Vetsch, David F.; et al. (2023)
Proceedings of the 9th International SUT Offshore Site Investigation and Geotechnics: Innovative Geotechnologies for Energy Transition
Historical chronicles together with geophysical, geotechnical, and sedimentological investigations have demonstrated that both subaqueous and subaerial landslides can lead to tsunamis on lakes. Previous work has shown that lakes in the alpine and peri-alpine settings in Switzerland provide prime preconditions for subaqueous mass movements, due to the glacially excavated basin geometry, the continuous sediment supply, and the related mechanical characteristics of the slopes. In addition, steep alongshore topography favours subaerial mass movements. The increasing settlement and infrastructure development along the shores and the lake tsunami history emphasize that assessing the tsunami hazard on Swiss peri-alpine lakes is essential. In a holistic approach that combines limnogeological, geomorphological, seismological, geotechnical, geospatial techniques with hydrodynamic simulations, we construct a workflow for the assessment of the landslide-tsunami hazard on peri-alpine lakes. GPU-accelerated numerical simulation using the freely available software BASEMENT allows for a rapid calculation of various inundation parameter distributions, considering uncertainties in landslide parameters. In the workflow, tsunami generation can be simulated both for subaqueous and subaerial mass movements. Hence, the hazard of lake tsunamis can be assessed comprehensively. Next to presenting the workflow, we provide recommendations for future work.
Systematic comparison of 1D and 2D hydrodynamic models for the assessment of hydropeaking alterations
Bürgler, Matthias; Vetsch, David F.; Boes, Robert; et al. (2023)
River Research and Applications
Numerical hydrodynamic models enable the simulation of hydraulic conditions under various scenarios and are thus suitable tools for hydropeaking related assessments. However, the choice of the necessary model complexity and the consequences of modelling choices are not trivial and only few guidelines exist. In this study, we systematically evaluate numerical one-dimensional (1D) and two-dimensional (2D) hydrodynamic models with varying spatial resolution regarding their suitability as input for hydropeaking-sensitive, ecologically relevant hydraulic parameters (ERHPs), and their computational efficiency. The considered ERHPs include the vertical dewatering velocity, the wetted area variation between base and peak flow and the bed shear stress as a proxy for macroinvertebrate drift. Furthermore, we quantified the habitat suitability of brown trout for different life stages. The evaluation is conducted for three channel planforms with morphological characteristics representative for regulated Alpine Rivers, ranging from alternating bars to a braiding river morphology. For the prediction of habitat suitability and bed shear stress, a 1D model appears to be always insufficient, and a highly resolved 2D model is suggested. Reducing the spatial resolution of 2D models leads to computational efficiency similar to 1D, while providing more accurate results. Thus, our results suggest, that while a highly resolved 1D model is sufficient for accurate predictions of the dewatering velocity and wetted area in the less complex alternating bar morphology, a 2D model is recommended for more complex wandering or braiding morphologies. This study can serve as guideline for researchers and practitioners in the selection and setup of hydrodynamic models for hydropeaking.
Effect of invert roughness on smooth spillway chute flow
Bürgler, Matthias; Vetsch, David F.; Boes, Robert; et al. (2023)
Role of Dams and Reservoirs in a Successful Energy Transition
Spillway chutes are appurtenant dam outlet structures with the purpose to safely convey large discharges during extreme flood events. During such events, hydraulics plays a major role in the safety of the structure. Along a spillway chute, water is accelerated by gravity and may reach flow velocities in the order of 10 to 50 m/s, implying a considerable cavitation risk. On the spillway invert, turbulence is generated by shear stresses and surface roughness, which results in self-aeration of the flow once the turbulent boundary layer interacts with the free surface. For reliable design guidelines of spillways, knowledge of air concentrations along the spillway chute is essential, as entrained air concentrations can mitigate the risk of cavitation at the expense of risking overtopping of the chute walls due to flow bulking, or further accelerating the flow due to drag reduction. While it is well known that the invert roughness is the controlling parameter for boundary layer development and the self-aeration process (for a given slope and discharge), the quantitative understanding of roughness effects on air-water flow properties is still limited by the availability of data sets that target this variable. In this research, the effects of invert roughness on smooth spillway chute flow are investigated in a large-scale physical model. The investigated flow properties include the clear water and air-water mixture flow depths, depth-averaged flow velocities, air concentrations, and friction factors. Based on the experimental data, we demonstrate that the streamwise development of depth-averaged air concentration is significantly affected by invert roughness, which in turn also affects the bottom air concentration downstream of the inception point. Further, we found that friction factors are significantly affected by the relative boundary layer thickness in the developing non-aerated flow region, but also by bottom air concentrations in the aerated flow region. Good agreement between experimentally determined friction factors and established theoretical relations was found. Overall, our findings contribute to a qualitative description of invert roughness effects on air-water flow properties for a robust design of spillways, thus contributing to safer dam infrastructure.
Basement V4—A Multipurpose Modelling Environment for Simulation of Flood Hazards and River Morphodynamics Across Scales
Vetsch, David F.; Wild, Seline; Halso, Matthew Christopher; et al. (2024)
Advances in Hydroinformatics - SimHydro 2023: New Modelling Paradigms for Water Issues
The numerical modelling of hydro- and morphodynamics in watercourses is of great importance for both the advancement of scientific understanding of under lying processes and for design in engineering practice. For this purpose, and focusing on alpine and subalpine conditions, the modelling software BASEMENT has been developed in the last two decades. The simulation environment is currently composed by different tools, either freeware or open-source. BASEMENT version 4 consists of two main modules, namely BASEMD (MD—Multi Domain) and BASEHPC (HPC—High Performance Computing). The software provides a unified simula tion workflow and graphical user interface for setting up numerical models with both modules. BASEMD offers multiple options to couple 1D and 2D domains, whilst BASEHPC supports both the use of multi-core processors and general-purpose graphics processing units (GPGPUs) to increase calculation efficiency. This can speed up simulations many times over, depending on the problem at hand. In both modules, the hydrodynamics is calculated based on the shallow water equations whilst morphodynamics accounts for both bed- and suspended load transport. In the present contribution some application possibilities of the software will be illustrated
Basement v3: a modular freeware for river process modelling over multiple computational backends
Vanzo, Davide; Peter, Samuel; Vonwiller, Lukas; et al. (2021)
Environmental Modelling & Software
Modelling river physical processes is of critical importance for flood protection, river management and restoration of riverine environments. Developments in algorithms and computational power have led to a wider spread of river simulation tools. However, the use of two-dimensional models can still be hindered by complexity in the setup and the high computational costs. Here we present the freeware basement version 3, a flexible tool for two-dimensional river simulations that bundles solvers for hydrodynamic, morphodynamic and scalar advection-diffusion processes. basement leverages different computational platforms (multi-core CPUs and graphics processing units GPUs) to enable the simulation of large domains and long-term river processes. The adoption of a fully costless workflow and a light GUI facilitate its broad utilization. We test its robustness and efficiency in a selection of benchmarks. Results confirm that basement could be an efficient and versatile tool for research, engineering practice and education in river modelling.
Auswirkung der Sohlenrauheit von Schussrinnen auf die Entwicklung der Wasser-Luft-Strömung
Friz, Carolin; Bürgler, Matthias; Hohermuth, Benjamin; et al. (2025)
WasserWirtschaft
Schussrinnen an Talsperren sichern die Hochwasserableitung. Ihre steilen Neigungen führen zu einer schwerkraftbedingten Beschleunigung des Abflusses, die an der Gerinnesohle Turbulenzen erzeugt und zur Selbstbelüftung des Abflusses führt. Ein angemessenes Prozessverständnis ist für die präzise Schussrinnenbemessung entscheidend. An einem großskaligen Versuchsmodell wurden mit modernster Messtechnik umfassende Experimente durchgeführt, deren Ergebnisse zur Kenntnis über hochenergetische Wasser-Luft-Strömungen und die Dimensionierung von Hochwasserentlastungsanlagen beitragen. Reservoir dams are critical for hydropower, irrigation, and flood protection, with spillways serving as essential safety outlets for flood waters. Their steep slopes produce high flow velocities, while turbulence at the spillway invert interacts with the free surface to induce self-aeration, resulting in “white waters”. A thorough understanding of these phenomena is vital for the robust design of spillways. However, progress in quantitatively describing these processes is limited by scarce, comprehensive air-water flow data downstream of the aeration inception point. Experiments on a large-scale physical model, with systematic variations in discharge and invert roughness, employed advanced instrumentation such as laser Doppler anemometry and dual-tip conductivity probes to measure flow velocities and air concentrations. Video analysis was used to determine a reference inception point. This study deepens our insight into high energy air-water flows and supports improved design of spillways.
Uncertainties in measurements of bubbly flows using phase-detection probes
Bürgler, Matthias; Valero, Daniel; Hohermuth, Benjamin; et al. (2024)
International Journal of Multiphase Flow
The analysis of bubbly two-phase flows is challenging due to their turbulent nature and the need for intrusive phase-detection probes. However, accurately characterizing these flows is crucial for safely designing critical infrastructure such as dams and their appurtenant structures. The combination of dual-tip intrusive phase-detection probes with advanced signal processing algorithms enables the assessment of pseudo-instantaneous 1-D velocity time series; for which the limitations are not fully fathomed. In this investigation, we theoretically define four major sources of error, which we quantify using synthetically generated turbulent time series, coupled with the simulated response of a phase-detection probe. Based on the analysis of 10¹⁰ simulated bubble trajectories, our findings show that typical high-velocity flows in hydraulic structures hold up to 15% error in the mean velocity estimations and up to 35% error in the turbulence intensity estimations for the most critical conditions, typically occurring in the proximity of the wall. Based on thousands of simulations, our study provides a novel data-driven tool for the estimation of these baseline errors (bias and uncertainties) in real-word phase-detection probe measurements of bubbly flows (air concentrations c < 40%).
Density-based turbulence damping at large-scale interface for Reynolds-averaged two-fluid models
Dong, Zongshi; Bürgler, Matthias; Hohermuth, Benjamin; et al. (2022)
Chemical Engineering Science
The overestimation of turbulence near large-scale interfaces in Reynolds-averaged per-phase turbulence models is a well-known problem. Herein, this is addressed by analyzing the turbulence transport equations and identifying the intrinsic limitation in the formulation of per-phase turbulence models for stratified flow. A novel density-based turbulence damping approach is proposed and compared to a conventional phenomenological damping model and a mixture model for pressurized co- and counter-current as well as gravity-driven stratified air-water flows. The novel approach performs well for all test cases. It is shown that the turbulence damping in the less dense phase is more important than that towards the denser phase. The density-based damping approach leads to more realistic turbulent kinetic energy profiles across the interface region compared to typical existing phenomenological damping approaches. Further, the novel approach does not rely on calibration parameters nor interface indicator functions and is thus well suited for further development of per-phase generalized models.
Hydronumerischen 1-D und 2-D-Modelle - Eignung zur Beurteilung der Auswirkungen von Schwall und Sunk
Bürgler, Matthias; Wicki, Timo; Vanzo, Davide; et al. (2019)
Wasser Energie Luft
Ansatz zur Modellierung von See-Tsunamis, ausgelöst durch terrestrische Massenbewegungen
Strupler, Michael; Schierjott, Jana; Bürgler, Matthias; et al. (2024)
Wasser Energie Luft

Publications 1 - 10 of 18

Matthias Bürgler

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