@article{HavermannBeylich1997,
  author    = {Havermann, Marc and Beylich, A. E.},
  title     = {Performance and Limitations of the Laser-Induced Fluorescence Measurement Technique and the Established Experimental Methods for the Study of Supersonic Mixing / Havermann, M. ; Beylich, A. E.},
  series = {International Journal of heat and technology. 15 (1997), H. 2},
  journal   = {International Journal of heat and technology. 15 (1997), H. 2},
  publisher = {-},
  pages     = {3 -- 10},
  year      = {1997},
  language  = {en}
}
@article{Havermann2005,
  author    = {Havermann, Marc},
  title     = {Effects of the shock tube open-end shape on vortex loops released from it / Kainuma, M. ; Havermann, M. ; Sun, M. ; Takayama, K.},
  series = {Shock Waves : Proceedings of the 24th International Symposium on Shock Waves Beijing, China July 11-16, 2004 / edited by Z. Jiang},
  journal   = {Shock Waves : Proceedings of the 24th International Symposium on Shock Waves Beijing, China July 11-16, 2004 / edited by Z. Jiang},
  publisher = {Springer},
  address   = {Berlin},
  isbn      = {978-3-540-22497-6},
  pages     = {505 -- 510},
  year      = {2005},
  language  = {en}
}
@article{HavermannSeilerBolleretal.2005,
  author    = {Havermann, Marc and Seiler, F. and Boller, F. and Mangold, P.},
  title     = {Operation of the ISL transonic shock tube in a high subsonic flow regime / Seiler, F. ; Havermann, M. ; Boller, F. ; Mangold, P. ; Takayama K.},
  series = {Shock Waves : Proceedings of the 24th International Symposium on Shock Waves Beijing, China July 11-16, 2004 / edited by Z. Jiang},
  journal   = {Shock Waves : Proceedings of the 24th International Symposium on Shock Waves Beijing, China July 11-16, 2004 / edited by Z. Jiang},
  publisher = {Springer},
  address   = {Berlin},
  isbn      = {978-3-540-22497-6},
  pages     = {307 -- 312},
  year      = {2005},
  language  = {en}
}
@article{HavermannEndeSeileretal.2005,
  author    = {Havermann, Marc and Ende, H. and Seiler, F. and Schwenzer, M.},
  title     = {Shock tunnel measurement of the interaction amplification factor for a hot gas side jet in a supersonic cross flow / Havermann, M. ; Ende, H. ; Seiler, F. ; Schwenzer, M.},
  series = {Shock Waves : Proceedings of the 24th International Symposium on Shock Waves Beijing, China July 11-16, 2004 / edited by Z. Jiang},
  journal   = {Shock Waves : Proceedings of the 24th International Symposium on Shock Waves Beijing, China July 11-16, 2004 / edited by Z. Jiang},
  publisher = {Springer},
  address   = {Berlin},
  isbn      = {978-3-540-22497-6},
  pages     = {113 -- 118},
  year      = {2005},
  language  = {en}
}
@book{HavermannSeilerGeorgeetal.2004,
  author    = {Havermann, Marc and Seiler, F. and George, A. and Srulijes, J.},
  title     = {Doppler Picture Velovimetry (DPV) applied to high speed shock tunnel flows : 11th International Symposium on Flow Visualization, University of Notre Dame, Notre Dame/IN, USA, August 9 - 12, 2004 / Institut Franco-Allemand de Recherches de Saint-Louis. Seiler, F. ...},
  publisher = {ISL},
  address   = {Saint-Louis},
  year      = {2004},
  language  = {en}
}
@article{ZiemonsHerzogFeinendegen1990,
  author    = {Ziemons, Karl and Herzog, H. and Feinendegen, L. E.},
  title     = {Iterative image reconstruction with weighted pixel contribution to projection element},
  series = {European Journal of Nuclear Medicine},
  volume    = {16},
  journal   = {European Journal of Nuclear Medicine},
  number    = {7},
  isbn      = {1619-7089},
  pages     = {403 -- 403},
  year      = {1990},
  language  = {en}
}
@article{Ziemons1991,
  author    = {Ziemons, Karl},
  title     = {Comparison of forward hadrons produced in muon interactions on nuclear targets and deuterium},
  series = {Zeitschrift f{\"u}r Physik C Particles and Fields},
  volume    = {52},
  journal   = {Zeitschrift f{\"u}r Physik C Particles and Fields},
  number    = {1},
  isbn      = {1431-5858},
  pages     = {1 -- 11},
  year      = {1991},
  abstract  = {Differential multiplicities of forward produced hadrons in deep inelastic muon scattering on nuclear targets have been compared with those from deuterium. The ratios are observed to increase towards unity as the virtual photon energy increases with no significant dependence on the other muon kinematic variables. The hadron transverse momentum distribution is observed to be broadened in nuclear targets. The dependence on the remaining hadron variables is investigated and the results are discussed in the framework of intranuclear interaction models and in the context of the EMC effect.},
  language  = {en}
}
@article{Ziemons1992,
  author    = {Ziemons, Karl},
  title     = {Muoproduction of J/ψ and the gluon distribution of the nucleon},
  series = {Zeitschrift f{\"u}r Physik C Particles and Fields},
  volume    = {56},
  journal   = {Zeitschrift f{\"u}r Physik C Particles and Fields},
  number    = {1},
  isbn      = {1431-5858},
  pages     = {21 -- 28},
  year      = {1992},
  abstract  = {Measurements are presented of the inclusive distributions of the J/Ψ meson produced by muons of energy 200 GeV from an ammonia target. The gluon distribution of the nucleon has been derived from the data in the range 0.04<x<0.36 using a technique based on the colour singlet model. An arbitrary normalisation factor is required to obtain a reasonable integral of the gluon distribution. Some comments are made on the use of J/Ψ productionby virtual photons to extract the gluon distribution at HERA.},
  language  = {en}
}
@article{ZiemonsHerzogBosettietal.1992,
  author    = {Ziemons, Karl and Herzog, H. and Bosetti, P. and Feinendegen, L. E.},
  title     = {Iterative image reconstruction with weighted pixel contribution to projection elements},
  series = {European Journal of Nuclear Medicine},
  volume    = {19},
  journal   = {European Journal of Nuclear Medicine},
  number    = {8},
  isbn      = {1619-7089},
  pages     = {588 -- 588},
  year      = {1992},
  language  = {en}
}
@article{Ziemons1993,
  author    = {Ziemons, Karl},
  title     = {A measurement of the ratio of the nucleon structure function in copper and deuterium},
  series = {Zeitschrift f{\"u}r Physik C Particles and Fields},
  volume    = {57},
  journal   = {Zeitschrift f{\"u}r Physik C Particles and Fields},
  number    = {2},
  isbn      = {1431-5858},
  pages     = {211 -- 218},
  year      = {1993},
  abstract  = {Results are presented on the ratios of the nucleon structure function in copper to deuterium from two separate experiments. The data confirm that the nucleon structure function,F 2, is different for bound nucleons than for the quasi-free ones in the deuteron. The redistribution in the fraction of the nucleon's momentum carried by quarks is investigated and it is found that the data are compatible with no integral loss of quark momenta due to nuclear effects.},
  language  = {en}
}
@article{BoeckerKuwertLangenetal.1994,
  author    = {Boecker, Henning and Kuwert, Torsten and Langen, Karl-J. and Lange, Herwig W. and Czech, Norbert and Ziemons, Karl and Herzog, Hans and Shikare, Shekar and Weindl, Anton and Feinendegen, Ludwig E.},
  title     = {SPECT with HMPAO compared to PET with FDG in Huntington disease},
  series = {Journal of Computer Assisted Tomography},
  volume    = {18},
  journal   = {Journal of Computer Assisted Tomography},
  number    = {4},
  isbn      = {1532-3145},
  pages     = {542 -- 548},
  year      = {1994},
  language  = {en}
}
@article{KowalskiMcElwaine2013,
  author    = {Kowalski, Julia and McElwaine, Jim N.},
  title     = {Shallow two-component gravity-driven flows with vertical variation},
  series = {Journal of Fluid Mechanics},
  volume    = {714},
  journal   = {Journal of Fluid Mechanics},
  publisher = {Cambridge Univ. Press},
  address   = {Cambridge},
  isbn      = {0022-1120},
  pages     = {434 -- 462},
  year      = {2013},
  language  = {en}
}
@article{OlaruKowalskiSethietal.2012,
  author    = {Olaru, Alexandra Maria and Kowalski, Julia and Sethi, Vaishali and Bl{\"u}mich, Bernhard},
  title     = {Exchange relaxometry of flow at small P{\´e}clet numbers in a glass bead pack},
  series = {Journal of Magnetic Resonance (JMR)},
  volume    = {220},
  journal   = {Journal of Magnetic Resonance (JMR)},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1096-0856},
  doi       = {10.1016/j.jmr.2012.04.015},
  pages     = {32 -- 44},
  year      = {2012},
  abstract  = {In this paper we consider low P{\´e}clet number flow in bead packs. A series of relaxation exchange experiments has been conducted and evaluated by ILT analysis. In the resulting correlation maps, we observed a collapse of the signal and a translation towards smaller relaxation times with increasing flow rates, as well as a signal tilt with respect to the diagonal. In the discussion of the phenomena we present a mathematical theory for relaxation exchange experiments that considers both diffusive and advective transport. We perform simulations based on this theory and discuss them with respect to the conducted experiments.},
  language  = {en}
}
@article{FischerKowalskiPudasaini2012,
  author    = {Fischer, Jan-Thomas and Kowalski, Julia and Pudasaini, Shiva P.},
  title     = {Topographic curvature effects in applied avalanche modelling},
  series = {Cold Regions Science and Technology},
  volume    = {74-75},
  journal   = {Cold Regions Science and Technology},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1872-7441},
  doi       = {10.1016/j.coldregions.2012.01.005},
  pages     = {21 -- 30},
  year      = {2012},
  abstract  = {This paper describes the implementation of topographic curvature effects within the RApid Mass MovementS (RAMMS) snow avalanche simulation toolbox. RAMMS is based on a model similar to shallow water equations with a Coulomb friction relation and the velocity dependent Voellmy drag. It is used for snow avalanche risk assessment in Switzerland. The snow avalanche simulation relies on back calculation of observed avalanches. The calibration of the friction parameters depends on characteristics of the avalanche track. The topographic curvature terms are not yet included in the above mentioned classical model. Here, we fundamentally improve this model by mathematically and physically including the topographic curvature effects. By decomposing the velocity dependent friction into a topography dependent term that accounts for a curvature enhancement in the Coulomb friction, and a topography independent contribution similar to the classical Voellmy drag, we construct a general curvature dependent frictional resistance, and thus propose new extended model equations. With three site-specific examples, we compare the apparent frictional resistance of the new approach, which includes topographic curvature effects, to the classical one. Our simulation results demonstrate substantial effects of the curvature on the flow dynamics e.g., the dynamic pressure distribution along the slope. The comparison of resistance coefficients between the two models demonstrates that the physically based extension presents an improvement to the classical approach. Furthermore a practical example highlights its influence on the pressure outline in the run out zone of the avalanche. Snow avalanche dynamics modeling natural terrain curvature centrifugal force friction coefficients.},
  language  = {en}
}
@article{BuehlerChristenKowalskietal.2011,
  author    = {B{\"u}hler, Yves and Christen, Marc and Kowalski, Julia and Bartelt, Perry},
  title     = {Sensitivity of snow avalanche simulations to digital elevation model quality and resolution},
  series = {Annals of Glaciology},
  volume    = {52},
  journal   = {Annals of Glaciology},
  number    = {58},
  publisher = {Cambridge University Press},
  address   = {Cambridge},
  isbn      = {1727-5644},
  pages     = {72 -- 80},
  year      = {2011},
  abstract  = {Digital elevation models (DEMs), represent the three-dimensional terrain and are the basic input for numerical snow avalanche dynamics simulations. DEMs can be acquired using topographic maps or remote-sensing technologies, such as photogrammetry or lidar. Depending on the acquisition technique, different spatial resolutions and qualities are achieved. However, there is a lack of studies that investigate the sensitivity of snow avalanche simulation algorithms to the quality and resolution of DEMs. Here, we perform calculations using the numerical avalance dynamics model RAMMS, varying the quality and spatial resolution of the underlying DEMs, while holding the simulation parameters constant. We study both channelized and open-terrain avalanche tracks with variable roughness. To quantify the variance of these simulations, we use well-documented large-scale avalanche events from Davos, Switzerland (winter 2007/08), and from our large-scale avalanche test site, Valĺee de la Sionne (winter 2005/06). We find that the DEM resolution and quality is critical for modeled flow paths, run-out distances, deposits, velocities and impact pressures. Although a spatial resolution of ~25 m is sufficient for large-scale avalanche modeling, the DEM datasets must be checked carefully for anomalies and artifacts before using them for dynamics calculations.},
  language  = {en}
}
@article{ChristenBarteltKowalski2010,
  author    = {Christen, Marc and Bartelt, Perry and Kowalski, Julia},
  title     = {Back calculation of the In den Arelen avalanche with RAMMS: Interpretation of model results},
  series = {Annals of Glaciology},
  volume    = {51},
  journal   = {Annals of Glaciology},
  number    = {54},
  publisher = {Cambridge University Press},
  address   = {Cambridge},
  isbn      = {1727-5644},
  doi       = {10.3189/172756410791386553},
  pages     = {161 -- 168},
  year      = {2010},
  abstract  = {Two- and three-dimensional avalanche dynamics models are being increasingly used in hazard-mitigation studies. These models can provide improved and more accurate results for hazard mapping than the simple one-dimensional models presently used in practice. However, two- and three-dimensional models generate an extensive amount of output data, making the interpretation of simulation results more difficult. To perform a simulation in three-dimensional terrain, numerical models require a digital elevation model, specification of avalanche release areas (spatial extent and volume), selection of solution methods, finding an adequate calculation resolution and, finally, the choice of friction parameters. In this paper, the importance and difficulty of correctly setting up and analysing the results of a numerical avalanche dynamics simulation is discussed. We apply the two-dimensional simulation program RAMMS to the 1968 extreme avalanche event In den Arelen. We show the effect of model input variations on simulation results and the dangers and complexities in their interpretation.},
  language  = {en}
}
@article{ChristenKowalskiBartelt2010,
  author    = {Christen, Marc and Kowalski, Julia and Bartelt, Perry},
  title     = {RAMMS: Numerical simulation of dense snow avalanches in three-dimensional terrain},
  series = {Cold Regions Science and Technology},
  volume    = {63},
  journal   = {Cold Regions Science and Technology},
  number    = {1-2},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1872-7441},
  doi       = {10.1016/j.coldregions.2010.04.005},
  pages     = {1 -- 14},
  year      = {2010},
  abstract  = {Numerical avalanche dynamics models have become an essential part of snow engineering. Coupled with field observations and historical records, they are especially helpful in understanding avalanche flow in complex terrain. However, their application poses several new challenges to avalanche engineers. A detailed understanding of the avalanche phenomena is required to construct hazard scenarios which involve the careful specification of initial conditions (release zone location and dimensions) and definition of appropriate friction parameters. The interpretation of simulation results requires an understanding of the numerical solution schemes and easy to use visualization tools. We discuss these problems by presenting the computer model RAMMS, which was specially designed by the SLF as a practical tool for avalanche engineers. RAMMS solves the depth-averaged equations governing avalanche flow with accurate second-order numerical solution schemes. The model allows the specification of multiple release zones in three-dimensional terrain. Snow cover entrainment is considered. Furthermore, two different flow rheologies can be applied: the standard Voellmy-Salm (VS) approach or a random kinetic energy (RKE) model, which accounts for the random motion and inelastic interaction between snow granules. We present the governing differential equations, highlight some of the input and output features of RAMMS and then apply the models with entrainment to simulate two well-documented avalanche events recorded at the Vall{\´e}e de la Sionne test site.},
  language  = {en}
}
@article{FischerKowalskiPudasainietal.2009,
  author    = {Fischer, Jan-Thomas and Kowalski, Julia and Pudasaini, Shiva P. and Miller, S. A.},
  title     = {Dynamic Avalanche Modeling in Natural Terrain},
  series = {International Snow Science Workshop, Davos 2009, Proceedings ; Proc. ISSW 2009},
  journal   = {International Snow Science Workshop, Davos 2009, Proceedings ; Proc. ISSW 2009},
  pages     = {448 -- 452},
  year      = {2009},
  abstract  = {The powerful avalanche simulation toolbox RAMMS (Rapid Mass Movements) is based on a depth-averaged hydrodynamic system of equations with a Voellmy-Salm friction relation. The two empirical friction parameters μ and � correspond to a dry Coulomb friction and a viscous resistance, respectively. Although μ and � lack a proper physical explanation, 60 years of acquired avalanche data in the Swiss Alps made a systematic calibration possible. RAMMS can therefore successfully model avalanche flow depth, velocities, impact pressure and run out distances. Pudasaini and Hutter (2003) have proposed extended, rigorously derived model equations that account for local curvature and twist. A coordinate transformation into a reference system, applied to the actual mountain topography of the natural avalanche path, is performed. The local curvature and the twist of the avalanche path induce an additional term in the overburden pressure. This leads to a modification of the Coulomb friction, the free-surface pressure gradient, the pressure induced by the channel, and the gravity components along and normal to the curved and twisted reference surface. This eventually guides the flow dynamics and deposits of avalanches. In the present study, we investigate the influence of curvature on avalanche flow in real mountain terrain. Simulations of real avalanche paths are performed and compared for the different models approaches. An algorithm to calculate curvature in real terrain is introduced in RAMMS. This leads to a curvature dependent friction relation in an extended version of the Voellmy-Salm model equations. Our analysis provides yet another step in interpreting the physical meaning and significance of the friction parameters used in the RAMMS computational environment.},
  language  = {en}
}
@inproceedings{ChristenBarteltKowalskietal.2008,
  author    = {Christen, Marc and Bartelt, Perry and Kowalski, Julia and Stoffel, Lukus},
  title     = {Calculation of dense snow avalanches in three-dimensional terrain with the numerical simulation programm RAMMS},
  series = {Proceedings ISSW 2008 ; International Snow Science Workshop. Whistler 2008},
  booktitle = {Proceedings ISSW 2008 ; International Snow Science Workshop. Whistler 2008},
  pages     = {709 -- 716},
  year      = {2008},
  abstract  = {Numerical models have become an essential part of snow avalanche engineering. Recent advances in understanding the rheology of flowing snow and the mechanics of entrainment and deposition have made numerical models more reliable. Coupled with field observations and historical records, they are especially helpful in understanding avalanche flow in complex terrain. However, the application of numerical models poses several new challenges to avalanche engineers. A detailed understanding of the avalanche phenomena is required to specify initial conditions (release zone dimensions and snowcover entrainment rates) as well as the friction parameters, which are no longer based on empirical back-calculations, rather terrain roughness, vegetation and snow properties. In this paper we discuss these problems by presenting the computer model RAMMS, which was specially designed by the SLF as a practical tool for avalanche engineers. RAMMS solves the depth-averaged equations governing avalanche flow with first and second-order numerical solution schemes. A tremendous effort has been invested in the implementation of advanced input and output features. Simulation results are therefore clearly and easily visualized to simplify their interpretation. More importantly, RAMMS has been applied to a series of well-documented avalanches to gauge model performance. In this paper we present the governing differential equations, highlight some of the input and output features of RAMMS and then discuss the simulation of the Gatschiefer avalanche that occurred in April 2008, near Klosters/Monbiel, Switzerland.},
  language  = {en}
}
@article{McArdellBarteltKowalski2007,
  author    = {McArdell, Brian W. and Bartelt, Perry and Kowalski, Julia},
  title     = {Field observations of basal forces and fluid pore pressure in a debris flow},
  series = {Geophysical Research Letters (GRL)},
  volume    = {34},
  journal   = {Geophysical Research Letters (GRL)},
  number    = {7},
  isbn      = {0094-8276},
  year      = {2007},
  abstract  = {Using results from an 8 m2 instrumented force plate we describe field measurements of normal and shear stresses, and fluid pore pressure for a debris flow. The flow depth increased from 0.1 to 1 m within the first 12 s of flow front arrival, remained relatively constant until 100 s, and then gradually decreased to 0.5 m by 600 s. Normal and shear stresses and pore fluid pressure varied in-phase with the flow depth. Calculated bulk densities are ρb = 2000-2250 kg m-3 for the bulk flow and ρf = 1600-1750 kg m-3 for the fluid phase. The ratio of effective normal stress to shear stress yields a Coulomb basal friction angle of ϕ = 26° at the flow front. We did not find a strong correlation between the degree of agitation in the flow, estimated using the signal from a geophone on the force plate, and an assumed dynamic pore fluid pressure. Our data support the idea that excess pore-fluid pressures are long lived in debris flows and therefore contribute to their unusual mobility.},
  language  = {en}
}