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A wave propagation laboratory for immersive experimentation

English title A wave propagation laboratory for immersive experimentation
Applicant Robertsson Johan O. A.
Number 157684
Funding scheme R'EQUIP
Research institution Institut für Geophysik ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Geophysics
Start/End 01.12.2014 - 30.11.2015
Approved amount 825'000.00
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All Disciplines (2)

Discipline
Geophysics
Other disciplines of Physics

Keywords (11)

immersive experimentation; data-driven focusing; experimental geophysics; physical modeling; low frequency; upscaling; cloaking; wave propagation; homogenization; time reversal; exact boundary conditions

Lay Summary (German)

Lead
Wellenausbreitungslabor für eingebundene ExperimenteLaboratoire acoustique pour l'experimentation immersiveDas Wellenausbreitungslabor ermöglicht es, die Interaktion seismischer Wellen mit Medien auf eine neue Art zu untersuchen. Dazu wird das physikalische Experiment in eine numerische Simulation eingebunden. Mögliche Anwendungen sind das Studium nicht-linearer Effekte und Experimente mit Medien, für die die Ausbreitung seismischer Wellen bisher nur unzureichend verstanden wird.
Lay summary

Inhalt und Ziel des Forschungsprojekts

Das Hauptziel des Projektes ist es jegliche Einschränkungen des Laborexperimentes aufgrund der limitierten physikalischen Größe zu überwinden. Dies erfordert, dass störende Reflektionen von den Wänden der Experimentapparatur durch realistische Reflektionen von zufälligen, virtuellen Strukturen außerhalb des Experimentes ersetzt werden. Dadurch wird eine übermäßige Skalierung des Experimentes und die Verwendung von hohen Frequenzen, welche die zu untersuchende, grundlegende Physik beeinträchtigen können, vermieden. Um dies zu erreichen, bedarf es eines Systems ähnlich eines Kopfhörers mit Störschallunterdrückung jedoch deutlich leistungsfähiger, welches hunderte von Sensoren und  Erzeugern ansteuert. Weitere Fragestellungen sind die Fokussierung von Wellen in stark streuenden Medien.

Wissenschaftlicher und gesellschaftlicher Kontext des Forschungsprojekts

Im wissenschaftlichen Kontext besteht die Gefahr, dass Laboruntersuchungen als Forschungsansatz von der Idee zur Anwendung aus dem Blickfeld verschwinden. Trotzdem sind sie von fundamentaler Bedeutung um Phänomene zu untersuchen, deren Physik kaum verstanden wird. Das Wellenausbreitungslabor ist ein Paradebeispiel für bessere, neuartige physikalische Akustikuntersuchungen, die helfen können diese wichtige Disziplin grundlegend neu zu beleben. Die gesellschaftliche Relevanz erstreckt sich von der Exploration und Produktion von Kohlenwasserstoffen über die Erkundung von Aquifern hin zu medizinischen Bildgebungsverfahren.

 

Direct link to Lay Summary Last update: 14.11.2014

Responsible applicant and co-applicants

Publications

Publication
Experimental Marchenko focusing in a 1D medium
Elison Patrick, Becker Theodor, van Manen Dirk-Jan, Donahue Carly, Broggini Filippo, Robertsson Johan (2016), Experimental Marchenko focusing in a 1D medium, in 2016 SEG annual Meeting, DallasSociety of Exploration Geophysicists, Tulsa.
Using a Marchenko-redatumed reflection response as an exact boundary condition
Schmidt Darren, Blum Thomas, Greenhalgh Stewart, van Manen Dirk-Jan, Robertsson Johan, Vasmel Marlies (2014), Using a Marchenko-redatumed reflection response as an exact boundary condition, GPU Technology Conference, San Diego.

Collaboration

Group / person Country
Types of collaboration
Petroleum Engineering and Applied Geophysics, NTNU Trondheim Norway (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Institut des Sciences de la Terre de Paris, UPMC Paris France (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Geophysics and Petrophysics group TU Delft Netherlands (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Institute of Geophysics, ETH Zurich Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
School of GeoSciences, University of Edinburgh Great Britain and Northern Ireland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure

Associated projects

Number Title Start Funding scheme
178342 Exhibition: Waves across the scales 01.04.2018 Agora
162360 Unlocking the near surface zone in seismic recordings: A paradigm shift in three-dimensional elastic modelling for full waveform inversion and non-linear laboratory experimentation 01.01.2016 Project funding
153089 New Developments of efficient geophysical tomography algortithms for exploring near-surface structures 01.05.2014 Project funding
144303 Unlocking the near surface zone in seismic recordings: A paradigm shift in three-dimensional elastic modelling for full waveform inversion and non-linear laboratory experimentation 01.01.2013 Project funding
140769 Full waveform seismic imaging of complex subsurface structures with application to resource exploration and development 01.07.2012 Project funding

Abstract

In most disciplines of physics, advances are enabled through a close symbiosis between theory and experiments. A theory is developed which then is tested in a laboratory under controlled conditions. Although there has been a resurgence of wave-based physical (laboratory) experi-mentation in applied geophysics in recent years, the limited physical size of the laborato-ries requires the use of wavelengths many orders of magnitude smaller than the target of inter-est such that interference from the edges of the laboratory can be avoided. Since the resulting frequencies that can be studied are several orders of magnitude higher than those typical of the exploration seismic or sonic frequency bands, this fundamentally limits the relevance of such experiments (Batzle et al., 2006). Recently, our group has proposed a new concept for wave propagation laboratories in which the physical experiment is linked with a numerical simulation in real time, exploiting a novel theory of exact boundary conditions (Vasmel et al., 2013; Robertsson et al., 2013; van Manen et al., 2007). The physical experiment and the numerical simulation interact at discrete time steps, so that the physical experiment is fully immersed within a larger numerical simulation domain, and the two domains interact with and drive each other. The interaction between the two domains takes place at the edges of the physical experiment where specific boundary conditions cause undesired boundary reflections to be cancelled. This enables imparting low-frequency signals on laboratory-scale targets independent of their size relative to the probing waves, including sub-wavelength scale. Furthermore, wave interactions with medium structures outside of the physical laboratory but represented within the numerical domain are automatically incorporated. A de-tailed feasibility study with National Instruments (NI) has resulted in a specification of the closed-loop real-time acquisition and control system using commercially available, expandable, scalable off-the-shelf NI technology that, meets the WaveLab’s strict dual requirements of low-latency and high-performance compute for systems of 800+ receivers and actuators, operating at 20 kHz. We thus request funds to acquire a real-time, closed-loop acquisition and control system to realize this unique and ground-breaking laboratory for immersive experimentation. The laboratory will enable research along at least three major directions: (1) low frequency ex-perimentation, (2) time-reversed acoustics and data-driven focusing, and (3) cloaking, upscaling and elastic experimentation. Regarding (1), we will undertake projects to characterise the re-sponse of fluid-filled porous media as well as to characterize seismo-electrical conversion and related phenomena. The targeted frequency range of 1 to 8 kHz, will allow us to perform measurements of properties at scales on the order of sonic logging, and with frequencies only one to two orders of magnitude above typical exploration seismic frequencies. On (2), we will undertake projects to experimentally demonstrate complete wavefield time-reversal and to research data-driven focusing. These topics are relevant for target reconstruction in complex media, which in turn are important in seismic exploration and related fields such as medical ultrasonic imaging and materials testing. These projects take advantage of the arbi-trary time-variant boundary conditions of the laboratory, completely surrounding the medium. On (3), we will undertake projects which further exploit these boundary conditions for cloaking and metamaterials experimentation. We will also take full advantage of the ability to do immer-sive experimentation to research upscaling and homogenization. The acquisition and control system that we request funding for is a powerful FPGA HPC facility in itself. We will exploit this substantial computational capacity for our research in solving computationally demanding partial differential equations and related geophysical inverse problems. Other research groups interested in HPC will also be making use of the FPGA cluster. Finally, the acquisition and control system is modular and can be reconfigured to also run other experiments that we expect to develop as part of the WaveLab.
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