TY  - JOUR
A1  - Fischer, Jan-Thomas
A1  - Kowalski, Julia
A1  - Pudasaini, Shiva P.
A1  - Miller, S. A.
T1  - Dynamic Avalanche Modeling in Natural Terrain
JF  - International Snow Science Workshop, Davos 2009, Proceedings ; Proc. ISSW 2009
N2  - 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.
KW  - snow
KW  - avalanche
Y1  - 2009
SP  - 448
EP  - 452
ER  - 
TY  - JOUR
A1  - Kowalski, Julia
A1  - Linder, Peter
A1  - Zierke, Simon
A1  - von Wulfen, Benedikt
A1  - Clemens, Joachim
A1  - Konstantinidis, Konstantinos
A1  - Ameres, Gerald
A1  - Hoffmann, Ruth
A1  - Mikucki, Jill A.
A1  - Tulaczyk, Slawek M.
A1  - Funke, Oliver
A1  - Blandfort, Daniel
A1  - Espe, Clemens
A1  - Feldmann, Marco
A1  - Francke, Gero
A1  - Hiecker, S.
A1  - Plescher, Engelbert
A1  - Schöngarth, Sarah
A1  - Dachwald, Bernd
A1  - Digel, Ilya
A1  - Artmann, Gerhard
A1  - Eliseev, Dmitry
A1  - Heinen, Dirk
A1  - Scholz, Franziska
A1  - Wiebusch, Christopher H.
A1  - Macht, Sabine
A1  - Bestmann, Ulf
A1  - Reineking, Thomas
A1  - Zetzsche, Christoph
A1  - Schill, Kerstin
A1  - Förstner, Roger
A1  - Niedermeier, Herbert
A1  - Szumski, Arkadiusz
A1  - Eissfeller, Bernd
A1  - Naumann, Uwe
A1  - Helbing, Klaus
T1  - Navigation technology for exploration of glacier ice with maneuverable melting probes
JF  - Cold Regions Science and Technology
N2  - The Saturnian moon Enceladus with its extensive water bodies underneath a thick ice sheet cover is a potential candidate for extraterrestrial life. Direct exploration of such extraterrestrial aquatic ecosystems requires advanced access and sampling technologies with a high level of autonomy. A new technological approach has been developed as part of the collaborative research project Enceladus Explorer (EnEx). The concept is based upon a minimally invasive melting probe called the IceMole. The force-regulated, heater-controlled IceMole is able to travel along a curved trajectory as well as upwards. Hence, it allows maneuvers which may be necessary for obstacle avoidance or target selection. Maneuverability, however, necessitates a sophisticated on-board navigation system capable of autonomous operations. The development of such a navigational system has been the focal part of the EnEx project. The original IceMole has been further developed to include relative positioning based on in-ice attitude determination, acoustic positioning, ultrasonic obstacle and target detection integrated through a high-level sensor fusion. This paper describes the EnEx technology and discusses implications for an actual extraterrestrial mission concept.
Y1  - 2016
U6  - https://doi.org/10.1016/j.coldregions.2015.11.006
SN  - 0165-232X
IS  - 123
SP  - 53
EP  - 70
PB  - Elsevier
CY  - Amsterdam
ER  -