Marianne Gjestvold Omang

• Omang, Marianne Gjestvold; Hauge, K.O. & Trulsen, Jan Karsten (2023). Combustion models for shock-induced cloud ignition of aluminium particles using smoothed particle hydrodynamics. Shock Waves. ISSN 0938-1287. doi: 10.1007/s00193-023-01148-z. Full text in Research Archive Show summary

  Abstract The present work is a numerical follow-up on our published experimental paper on shock ignition of aluminium particle clouds in the low-temperature regime. The in-house multi-phase regularized smoothed particle hydrodynamics (MP-RSPH) code is used to perform numerical simulations with an increasing degree of complexity, looking at single-phase, inert, and reactive particles in separate simulations. The first part of the paper gives a short description of the additional physics added to the code. Based on the experimental results, the numerical code is then used to estimate the particle temperature at the time of ignition. Results from simulations with three different numerical descriptions, the diffusive, kinetic, and total burn rates, are then compared to the experimental results. The two diffusive burn rate simulations (K &H and O &H) show the best fit to the experimental results. The burn rate formula based on our experimental data (O &H) is preferred, since it has the gas temperature dependency included and does not require additional parameter adjustments. The results from the numerical simulations support the theory that the observed aluminium particle cloud burning process is diffusive, as indicated in the experimental paper.

• Omang, Marianne Gjestvold & Hauge, Knut Ove (2022). Shock ignition of aluminium particle clouds in the low-temperature regime. Shock Waves. ISSN 0938-1287. 32(8), p. 691–701. doi: 10.1007/s00193-022-01108-z. Full text in Research Archive Show summary

  In this paper, we present results from spontaneous ignition of aluminium particle clouds in a series of shock tube experiments. For all experiments, the shock propagates along a narrow pile of 40-μm aluminium particles. The study includes shock Mach numbers in the range from 1.51 to 2.38. The results are visualised using photographic techniques and pressure gauges. The combination of two Phantom high-speed video cameras and a beamsplitter allows a compact schlieren setup mounted together with a dark-film high-speed camera. While the schlieren technique allows the shock features to be identified, the dark-film camera is used to capture the ignition and burning of the aluminium particle clouds. Based on extensive image processing and shock tube relations for reflected shocks, spontaneous ignition of the aluminium particle cloud is found to take place for reflected shock gas temperatures above 635 K. For increasing Mach numbers, we find a decreasing trend for the ignition delay. Additionally, the burning time is observed to decrease with increasing Mach number, indicating that the burning process is more efficient with increasing gas temperature.

• Osnes, Andreas Nygård; Vartdal, Magnus; Omang, Marianne Gjestvold & Reif, Bjørn Anders Pettersson (2020). Particle-resolved simulations of shock-induced flow through particle clouds at different Reynolds numbers. Physical Review Fluids. doi: 10.1103/PhysRevFluids.5.014305. Full text in Research Archive Show summary

  This study investigates the Reynolds-number dependence of shock-induced flow through stationary particle clouds at 10% volume fraction, using ensemble-averaged results from three-dimensional particle-resolved large eddy simulations. The advantage of using large eddy simulations to study this problem is that they capture the strong velocity shears and flow separation caused by the no-slip condition at the particle surfaces. The shock particle cloud interaction produces a reflected shock wave, whose strength increases with decreasing particle Reynolds number. This results in important changes to the flow field that enters the particle cloud. The results show an approximate proportionality between the mean flow velocity and the flow fluctuation magnitudes. Maximum particle drag forces are in excellent agreement with previous inviscid studies, and we complement these results with statistics of time-averaged particle forces as well as the variation of temporal oscillations. The results of this work provide a basis for development of improved simplified dispersed flow models.

• Osnes, Andreas Nygård; Vartdal, Magnus; Omang, Marianne Gjestvold & Reif, Bjørn Anders Pettersson (2019). Numerical investigation of shock wave particle cloud interaction in cylindrical geometries. In Skallerud, Bjørn Helge & Andersson, Helge Ingolf (Ed.), MekIT’19 - 10th National Conference on Computational Mechanics (Trondheim, Norway, 3-4 June 2019). International Center for Numerical Methods in Engineering (CIMNE). ISSN 9788494919497. p. 285–310. Full text in Research Archive
• Omang, Marianne Gjestvold; Hauge, Knut Ove & Trulsen, Jan Karsten (2019). Exploring the Capability of a New Shock Tube Facility to Investigate Shock Interaction with Inert Particle Columns. In Sasoh, Akihiro; Aoki, Toshiyuki & Katayama, Masahide (Ed.), 31st International Symposium on Shock Waves 2: Applications. Springer Nature. ISSN 9783319910161. p. 705–709. doi: 10.1007/978-3-319-91017-8_88. Full text in Research Archive
• Osnes, Andreas Nygård; Vartdal, Magnus; Omang, Marianne Gjestvold & Reif, Bjørn Anders Pettersson (2019). Computational analysis of shock-induced flow through stationary particle clouds. International Journal of Multiphase Flow. ISSN 0301-9322. doi: 10.1016/j.ijmultiphaseflow.2019.03.010. Full text in Research Archive Show summary

  We investigate the shock-induced flow through random particle arrays using particle-resolved Large Eddy Simulations for different incident shock wave Mach numbers, particle volume fractions and particle sizes. We analyze trends in mean flow quantities and the unresolved terms in the volume averaged momentum equation, as we vary the three parameters. We find that the shock wave attenuation and certain mean flow trends can be predicted by the opacity of the particle cloud, which is a function of particle size and particle volume fraction. We show that the Reynolds stress field plays an important role in the momentum balance at the particle cloud edges, and therefore strongly affects the reflected shock wave strength. The Reynolds stress was found to be insensitive to particle size, but strongly dependent on particle volume fraction. It is in better agreement with results from simulations of flow through particle clouds at fixed mean slip Reynolds numbers in the incompressible regime, than with results from other shock wave particle cloud studies, which have utilized either inviscid or two-dimensional approaches. We propose an algebraic model for the streamwise Reynolds stress based on the observation that the separated flow regions are the primary contributions to the Reynolds stress.

• Omang, Marianne Gjestvold & Trulsen, Jan Karsten (2017). Shock Ignition of Reactive Particles. In Ben-Dor, Gabi; Sadot, Oren & Igra, Ozer (Ed.), 30th International Symposium on Shock Waves 1. Springer. ISSN 9783319462110. p. 771–775. doi: 10.1007/978-3-319-46213-4_133. Full text in Research Archive
• Omang, Marianne Gjestvold & Trulsen, Jan Karsten (2014). Multi-phase shock simulations with smoothed particle hydrodynamics (SPH). Shock Waves. ISSN 0938-1287. 24(5), p. 521–536. doi: 10.1007/s00193-014-0506-7. Full text in Research Archive
• Omang, Marianne Gjestvold; Christensen, S. O.; Børve, Steinar & Trulsen, Jan Karsten (2009). Height of burst explosions: a comparative study of numerical and experimental results. Shock Waves. ISSN 0938-1287. 19(2), p. 135–143. doi: 10.1007/s00193-009-0196-8. Full text in Research Archive
• Børve, Steinar; Speith, Roland; Omang, Marianne Gjestvold & Trulsen, Jan Karsten (2007). Challenges related to particle regularization in SPH. In Crespo, Alejandro J.C.; Gómez-Gesteira, Moncho; Souto-Iglesias, Antonio; Delorme, Louis & Grassa, José María (Ed.), SPHERIC – Smoothed Particle Hydrodynamics European Research Interest Community: SECOND INTERNATIONAL WORKSHOP. Aica Ediciones. ISSN 9788469061596. p. 67–70. Full text in Research Archive
• Omang, Marianne Gjestvold; Børve, Steinar; Christensen, S. O. & Trulsen, Jan Karsten (2007). Symmetry assumptions in SPH. In Crespo, Alejandro J.C.; Gómez-Gesteira, Moncho; Souto-Iglesias, Antonio; Delorme, Louis & Grassa, José María (Ed.), SPHERIC – Smoothed Particle Hydrodynamics European Research Interest Community: SECOND INTERNATIONAL WORKSHOP. Aica Ediciones. ISSN 9788469061596. p. 103–106. Full text in Research Archive
• Omang, Marianne Gjestvold; Børve, Steinar & Trulsen, Jan Karsten (2007). Shock collisions in 3D using an axi-symmetric regularized smoothed particle hydrodynamics code. Shock Waves. ISSN 0938-1287. 16, p. 467–475. doi: 10.1007/s00193-007-0083-0. Full text in Research Archive
• Omang, Marianne Gjestvold; Børve, Steinar & Trulsen, Jan (2006). SPH in spherical and cylindrical coordinates. Journal of Computational Physics. ISSN 0021-9991. 213(1), p. 391–412. doi: 10.1016/j.jcp.2005.08.023. Full text in Research Archive
• Omang, Marianne Gjestvold; Børve, Steinar & Trulsen, Jan Karsten (2006). Numerical simulations of shock wave reflection phenomena in non-stationary flows using regularized smoothed particle hydrodynamics (RSPH). Shock Waves. ISSN 0938-1287. 16, p. 167–177. doi: 10.1007/s00193-006-0061-y. Full text in Research Archive
• Børve, Steinar; Omang, Marianne Gjestvold & Trulsen, Jan Karsten (2006). Multidimensional MHD Shock Tests of Regularized Smoothed Particle Hydrodynamics. The Astrophysical Journal (ApJ). ISSN 0004-637X. 652, p. 1306–1317. Full text in Research Archive
• Børve, Steinar; Omang, Marianne Gjestvold & Trulsen, Jan (2005). Regularized smoothed particle hydrodynamics with improved multi-resolution handling. Journal of Computational Physics. ISSN 0021-9991. 208, p. 345–367. Full text in Research Archive
• Omang, Marianne Gjestvold; Børve, Steinar & Trulsen, Jan (2005). Alternative kernel functions for Smoothed Particle Hydrodynamics in cylindrical symmetry. Shock Waves. ISSN 0938-1287. 14(4), p. 293–298. doi: 10.1007/s00193-005-0274-5. Full text in Research Archive
• Børve, Steinar; Omang, Marianne Gjestvold & Trulsen, Jan (2004). Two-dimensional MHD smoothed particle hydrodynamics stability analysis. Astrophysical Journal Supplement Series. ISSN 0067-0049. 153, p. 447–462. Full text in Research Archive

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• Omang, Marianne Gjestvold & Hauge, Knut Ove (2021). Spontaneous ignition of aluminum particles in a shock tube environment. Full text in Research Archive
• Trulsen, Jan Karsten & Omang, Marianne Gjestvold (2012). Shock propagation through bounded dust clouds. Full text in Research Archive
• Omang, Marianne Gjestvold; Christensen, Svein Olav; Hauge, Knut Ove & Trulsen, Jan Karsten (2011). A numerical and experimental study on charge geometries. Full text in Research Archive
• Omang, Marianne Gjestvold; Christensen, S. O.; Børve, Steinar & Trulsen, Jan Karsten (2010). Blast wave generation and propagation. Full text in Research Archive
• Omang, Marianne Gjestvold; Børve, Steinar & Trulsen, Jan Karsten (2006). Shock collision in 3D using Regularized Smoothed Particle Hydrodynamics method for cylinder symmetry. Full text in Research Archive
• Omang, Marianne Gjestvold; Børve, Steinar & Trulsen, Jan Karsten (2006). Blast wave simulations with an axis-symmetric RSPH code. Full text in Research Archive
• Omang, Marianne Gjestvold; Børve, Steinar & Trulsen, Jan Karsten (2006). Numerical simulations of blast wave interactions with barrier structures using Regularized Smoothed Particle Hydrodynamics (RSPH). Full text in Research Archive
• Omang, Marianne Gjestvold; Børve, Steinar & Trulsen, Jan (2004). Applications of SPH in spherically and cylindrically symmetric systems. Full text in Research Archive
• Omang, Marianne Gjestvold; Børve, Steinar & Trulsen, Jan (2004). Blast type shock phenomena simulated using regularized smoothed particle hydrodynamics. Full text in Research Archive
• Børve, Steinar; Omang, Marianne Gjestvold & Trulsen, Jan (2004). Simulating the Orszag-Tang vortex using RSPH. Full text in Research Archive
• Osnes, Andreas Nygård; Vartdal, Magnus; Reif, Bjørn Anders Pettersson & Omang, Marianne Gjestvold (2019). Shock-induced flow through particle clouds. Universitetet i Oslo. Full text in Research Archive Show summary

  High-speed flows through dense particle clouds occur in many technological applications such as explosion mitigation systems, combustion engines, drug-delivery systems, as well as natural phenomena such as volcanic eruptions and meteoroid breakup. This thesis studies such flows by means of numerical simulations. Typical flows of interest feature trillions of particles, and it is therefore necessary to use simplified models to describe the behaviour of the particles and the flow around them. In this thesis, we use very large, accurate, simulations to study the details of shock-induced flows with a moderate number of particles. In addition, full-scale simulations with a large number of particles are used to determine the sensitivity of such simulations to modelling choices. The simulations with few particles show that high particle concentration necessitates modifications to the drag-laws and flow model approximations that are used to simulate full-scale problems. Small-scale flow fluctuations affect the average flow statistics, and must be modelled in simulations where they are not directly captured. The full-scale simulations show that the shock-accelerated particles self-organise and form particle jets, in agreement with experiments. To capture this process, the simulations must account for the interchange of momentum and energy between the particles and the surrounding air.

• Omang, Marianne Gjestvold (2005). A Numerical Study of Shock Reflection Phenomena: Exploring the capabilities of Regularized Smoothed Particle Hydrodynamics to handle shock waves. Universitetet i Oslo. Full text in Research Archive

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