scholarly journals Numerical modeling of an avalanche impact against an obstacle with account of snow compressibility

2008 ◽  
Vol 49 ◽  
pp. 27-32 ◽  
Author(s):  
V.S. Kulibaba ◽  
M.E. Eglit
Keyword(s):  
Numerical Modeling ◽  
Equation Of State ◽  
Numerical Solution ◽  
Pressure Distribution ◽  
Time Dependent ◽  
Low Density ◽  
Two Dimensional ◽  
Dimensional Problem ◽  
Flow Depth ◽  
Rarefaction Waves

AbstractThe numerical solution to a time-dependent two-dimensional problem of an avalanche impact against a wall is presented. The height of the wall is much larger than the flow depth. Compressibility of the moving snow as well as the effect of gravity is taken into account. Calculations are made for an impact of low-density avalanches with densities <100 kgm–3 obeying the equation of state for a mixture of two gases (air and gas of ice/snow particles). The pressure, density and velocity distributions in the flow as functions of time and space coordinates are calculated, as well as the variation of the flow depth. In particular, the flow height at the wall, the pressure at the wall and the pressure distribution on the slope near the wall are given, demonstrating peaks and falls due to compression shocks and rarefaction waves.

scholarly journals Modeling Tidal Effects in Accretion Discs

1997 ◽  
Vol 163 ◽  
pp. 335-338
Author(s):  
Patrick Godon
Keyword(s):  
Equation Of State ◽  
White Dwarf ◽  
Accretion Discs ◽  
Time Dependent ◽  
Two Dimensional ◽  
Mass Ratio ◽  
Tidal Effects ◽  
Azimuthal Mode ◽  
Polytropic Equation

AbstractA two-dimensional time-dependent spectral code is used for the study of tidal effects in accretion discs. A cool disc around a white dwarf (characteristic of CV systems) is modeled under the assumption of a polytropic equation of state and a standard alpha viscosity prescription. For a mass ratio q < 0.1 (considered here) and under the assumption of a reflective inner boundary, tidal effects induce an eccentric (m=l azimuthal) mode in the disc together with an elliptic (m=2 azimuthal) mode in the inner disc.

ITPE Technique Applications to Time-Varying Three-Dimensional Ground-Coupling Problems

1990 ◽  
Vol 112 (4) ◽  
pp. 849-856 ◽  
Author(s):  
M. Krarti ◽  
D. E. Claridge ◽  
J. F. Kreider
Keyword(s):  
Heat Loss ◽  
Parametric Analysis ◽  
Three Dimensional ◽  
Time Dependent ◽  
Time Varying ◽  
Two Dimensional ◽  
Dimensional Problem ◽  
Dimensional Model ◽  
Approximate Analytical Solutions ◽  
Profile Estimation

Approximate analytical solutions for the three-dimensional heat transfer between slab-on-grade floors and rectangular basements under steady-periodic conditions are developed using the Interzone Temperature Profile Estimation (ITPE) method. The slab-on-grade solution is the first analytical slab-on-grade solution that treats the presence of insulation on/under the floor, while the basement solution is the first analytical solution of the time-dependent three-dimensional problem for basements. Solutions are given for the temperature field and expressions are derived for the annual heat loss. Parametric analysis is used to emphasize the effect of geometric dimensions on the magnitude and phase of heat loss relative to ambient temperature. The results obtained are compared with those from the two-dimensional model, and the three-dimensional characteristics of heat flow from slabs and basements are examined.

The inviscid transonic flow about a cylinder

1995 ◽  
Vol 301 ◽  
pp. 225-250 ◽  
Author(s):  
Nicola Botta
Keyword(s):  
Mach Number ◽  
Numerical Solution ◽  
Transonic Flow ◽  
Oscillating Solution ◽  
Time Dependent ◽  
Turbulent Regime ◽  
Two Dimensional ◽  
Chaotic Flow ◽  
Regular Flow ◽  
Upwind Method

The two-dimensional inviscid transonic flow about a circular cylinder is investigated. To do this, the Euler equations are integrated numerically with a time-dependent technique. The integration is based on an high-resolution finite volume upwind method.Time scales are introduced and the flow at very short, short and large times is studied. Attention is focused on the behaviour of the numerical solution at large times, after the breakdown of symmetry and the onset of an oscillating solution have occurred. This solution is known to be periodic at Mach number between 0.5 and 0.6.At higher speed, however, a richer behaviour is observed. As the Mach number is increased from 0.6 to 0.98 the numerical solution undergoes two transitions. Through a first one the periodical, regular flow enters a chaotic, turbulent regime. Through the second transition the chaotic flow comes back to an almost stationary state. The flow in the chaotic and in the almost stationary regimes is investigated. A numerical conjecture for the behaviour of the solution at large times is advanced.

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