TY  - JOUR
A1  - Havermann, Marc
A1  - Haertig, J.
A1  - Rey, C.
A1  - George, A.
T1  - PIV Measurements in Shock Tunnels and Shock Tubes / Havermann, M. ; Haertig, J. ; Rey, C. ; George, A.
JF  - Particle Image Velocimetry : New Developments and Recent Applications
Y1  - 2008
SN  - 978-3-540-73528-1
N1  - Topics in applied physics. Vol 112.
SP  - 429
EP  - 442
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Havermann, Marc
A1  - Seiler, F.
A1  - Georges, A.
A1  - Srulijes, J.
T1  - Progress in Doppler picture velocimetry (DPV) / Seiler, F. ; George, A. ; Srulijes, J. ; Havermann, M.
JF  - Experiments in Fluids. 44 (2008), H. 3
Y1  - 2008
SN  - 1432-1114
SP  - 389
EP  - 395
PB  - -
ER  - 
TY  - JOUR
A1  - Pichler, A.
A1  - George, A.
A1  - Seiler, F.
A1  - Srulijes, J.
A1  - Havermann, Marc
T1  - Doppler Picture Velocimetry (DPV) applied to hypersonics
JF  - Shock Waves [Elektronische Ressource] : 26th International Symposium on Shock Waves, Volume 1 / edited by Klaus Hannemann, Friedrich Seiler
Y1  - 2009
SN  - 978-3-540-85168-4
N1  - International Symposium on Shock Waves ; (26 ; 2007.07.15-20 ; Göttingen) ; ISSW ; (26 ; 2007.07.15-20 ; Göttingen)
SP  - 503
EP  - 508
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Havermann, Marc
A1  - Seiler, F.
A1  - George, A.
A1  - Leopold, F.
T1  - Planar Velocity Visualization in High-Speed Wedge Flow using Doppler Picture Velocimetry (DPV) compared with Particle Image Velocimetry (PIV) / Seiler, F. ; Havermann, M. ; George, A. ; Leopold, F. ; Srulijes, J.
JF  - Journal of Visualization. 6 (2003), H. 3
Y1  - 2003
SN  - 1343-8875
SP  - 253
EP  - 262
PB  - -
ER  - 
TY  - JOUR
A1  - Havermann, Marc
A1  - Beylich, A. E.
T1  - 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.
JF  - International Journal of heat and technology. 15 (1997), H. 2
Y1  - 1997
SP  - 3
EP  - 10
PB  - -
ER  - 
TY  - JOUR
A1  - Havermann, Marc
T1  - Effects of the shock tube open-end shape on vortex loops released from it / Kainuma, M. ; Havermann, M. ; Sun, M. ; Takayama, K.
JF  - Shock Waves : Proceedings of the 24th International Symposium on Shock Waves Beijing, China July 11-16, 2004 / edited by Z. Jiang
Y1  - 2005
SN  - 978-3-540-22497-6
SP  - 505
EP  - 510
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Havermann, Marc
A1  - Seiler, F.
A1  - Boller, F.
A1  - Mangold, P.
T1  - Operation of the ISL transonic shock tube in a high subsonic flow regime / Seiler, F. ; Havermann, M. ; Boller, F. ; Mangold, P. ; Takayama K.
JF  - Shock Waves : Proceedings of the 24th International Symposium on Shock Waves Beijing, China July 11-16, 2004 / edited by Z. Jiang
Y1  - 2005
SN  - 978-3-540-22497-6
SP  - 307
EP  - 312
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Havermann, Marc
A1  - Ende, H.
A1  - Seiler, F.
A1  - Schwenzer, M.
T1  - 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.
JF  - Shock Waves : Proceedings of the 24th International Symposium on Shock Waves Beijing, China July 11-16, 2004 / edited by Z. Jiang
Y1  - 2005
SN  - 978-3-540-22497-6
SP  - 113
EP  - 118
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Ziemons, Karl
A1  - Herzog, H.
A1  - Feinendegen, L. E.
T1  - Iterative image reconstruction with weighted pixel contribution to projection element
JF  - European Journal of Nuclear Medicine
Y1  - 1990
SN  - 1619-7089
N1  - Abstracts of the European Association of Nuclear Medicine Congress ; V52
VL  - 16
IS  - 7
SP  - 403
EP  - 403
ER  - 
TY  - JOUR
A1  - Ziemons, Karl
T1  - Comparison of forward hadrons produced in muon interactions on nuclear targets and deuterium
JF  - Zeitschrift für Physik C Particles and Fields
N2  - 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.
Y1  - 1991
SN  - 1431-5858
N1  - European Muon Collaboration
VL  - 52
IS  - 1
SP  - 1
EP  - 11
ER  - 
TY  - JOUR
A1  - Ziemons, Karl
T1  - Muoproduction of J/ψ and the gluon distribution of the nucleon
JF  - Zeitschrift für Physik C Particles and Fields
N2  - 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.
Y1  - 1992
SN  - 1431-5858
N1  - European Muon Collaboration
VL  - 56
IS  - 1
SP  - 21
EP  - 28
ER  - 
TY  - JOUR
A1  - Ziemons, Karl
A1  - Herzog, H.
A1  - Bosetti, P.
A1  - Feinendegen, L. E.
T1  - Iterative image reconstruction with weighted pixel contribution to projection elements
JF  - European Journal of Nuclear Medicine
Y1  - 1992
SN  - 1619-7089
N1  - Abstracts of the European Association of Nuclear Medicine Congress 23–26 August 1992 Lisboa, Portugal ; V143-2
VL  - 19
IS  - 8
SP  - 588
EP  - 588
ER  - 
TY  - JOUR
A1  - Ziemons, Karl
T1  - A measurement of the ratio of the nucleon structure function in copper and deuterium
JF  - Zeitschrift für Physik C Particles and Fields
N2  - 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.
Y1  - 1993
SN  - 1431-5858
N1  - European Muon Collaboration
VL  - 57
IS  - 2
SP  - 211
EP  - 218
ER  - 
TY  - JOUR
A1  - Boecker, Henning
A1  - Kuwert, Torsten
A1  - Langen, Karl-J.
A1  - Lange, Herwig W.
A1  - Czech, Norbert
A1  - Ziemons, Karl
A1  - Herzog, Hans
A1  - Shikare, Shekar
A1  - Weindl, Anton
A1  - Feinendegen, Ludwig E.
T1  - SPECT with HMPAO compared to PET with FDG in Huntington disease
JF  - Journal of Computer Assisted Tomography
Y1  - 1994
SN  - 1532-3145
VL  - 18
IS  - 4
SP  - 542
EP  - 548
ER  - 
TY  - JOUR
A1  - Kowalski, Julia
A1  - McElwaine, Jim N.
T1  - Shallow two-component gravity-driven flows with vertical variation
JF  - Journal of Fluid Mechanics
Y1  - 2013
SN  - 0022-1120
VL  - 714
SP  - 434
EP  - 462
PB  - Cambridge Univ. Press
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Olaru, Alexandra Maria
A1  - Kowalski, Julia
A1  - Sethi, Vaishali
A1  - Blümich, Bernhard
T1  - Exchange relaxometry of flow at small Péclet numbers in a glass bead pack
JF  - Journal of Magnetic Resonance (JMR)
N2  - In this paper we consider low Péclet 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.
KW  - NMR exchange relaxometry
KW  - Low-field NMR
Y1  - 2012
U6  - https://doi.org/10.1016/j.jmr.2012.04.015
SN  - 1096-0856
VL  - 220
SP  - 32
EP  - 44
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Fischer, Jan-Thomas
A1  - Kowalski, Julia
A1  - Pudasaini, Shiva P.
T1  - Topographic curvature effects in applied avalanche modelling
JF  - Cold Regions Science and Technology
N2  - 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.
KW  - Snow
KW  - Avalanche
Y1  - 2012
U6  - https://doi.org/10.1016/j.coldregions.2012.01.005
SN  - 1872-7441
VL  - 74-75
SP  - 21
EP  - 30
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Bühler, Yves
A1  - Christen, Marc
A1  - Kowalski, Julia
A1  - Bartelt, Perry
T1  - Sensitivity of snow avalanche simulations to digital elevation model quality and resolution
JF  - Annals of Glaciology
N2  - 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.
KW  - snow
KW  - avalanche
Y1  - 2011
SN  - 1727-5644
VL  - 52
IS  - 58
SP  - 72
EP  - 80
PB  - Cambridge University Press
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Christen, Marc
A1  - Bartelt, Perry
A1  - Kowalski, Julia
T1  - Back calculation of the In den Arelen avalanche with RAMMS: Interpretation of model results
JF  - Annals of Glaciology
N2  - 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.
KW  - avalanche
Y1  - 2010
SN  - 1727-5644
U6  - https://doi.org/10.3189/172756410791386553
VL  - 51
IS  - 54
SP  - 161
EP  - 168
PB  - Cambridge University Press
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Christen, Marc
A1  - Kowalski, Julia
A1  - Bartelt, Perry
T1  - RAMMS: Numerical simulation of dense snow avalanches in three-dimensional terrain
JF  - Cold Regions Science and Technology
N2  - 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 Vallée de la Sionne test site.
KW  - RAMMS
KW  - snow
KW  - avalanche
Y1  - 2010
U6  - https://doi.org/10.1016/j.coldregions.2010.04.005
SN  - 1872-7441
VL  - 63
IS  - 1-2
SP  - 1
EP  - 14
PB  - Elsevier
CY  - Amsterdam
ER  -