scholarly journals Back calculation of the In den Arelen avalanche with RAMMS: interpretation of model results

2010 ◽  
Vol 51 (54) ◽  
pp. 161-168 ◽  
Author(s):  
Marc Christen ◽  
Perry Bartelt ◽  
Julia Kowalski
Keyword(s):  
Numerical Models ◽  
Three Dimensional ◽  
Dynamics Simulation ◽  
Model Specification ◽  
Hazard Mapping ◽  
Avalanche Dynamics ◽  
Solution Methods ◽  
Simulation Results ◽  
Dimensional Models ◽  
Friction Parameters

AbstractTwo- 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.

LOW TEMPERATURE MODELS OF METAL OXIDE SEMICONDUCTOR FIELD-EFFECT TRANSISTORS

1995 ◽  
Vol 06 (02) ◽  
pp. 317-373 ◽  
Author(s):  
G. GILDENBLAT ◽  
D. FOTY
Keyword(s):  
Low Temperature ◽  
Field Effect Transistors ◽  
Numerical Models ◽  
Three Dimensional ◽  
Oxide Semiconductor ◽  
Characteristic Time Scale ◽  
Mos Transistors ◽  
Short Channel ◽  
Temperature Range ◽  
Dimensional Models

We review the modeling of silicon MOS devices in the 10–300 K temperature range with an emphasis on the specifics of low-temperature operation. Recently developed one-dimensional models of long-channel transistors are discussed in connection with experimental determination and verification of the effective channel mobility in a wide temperature range. We also present analytical pseudo-two-dimensional models of short-channel devices which have been proposed for potential use in circuit simulators. Several one-, two-, and three-dimensional numerical models are discussed in order to gain insight into the more subtle details of the low-temperature device physics of MOS transistors and capacitors. Particular attention is paid to freezeout effects which, depending on the device design and the ambient temperature range, may or may not be important for actual device operation. The numerical models are applied to study the characteristic time scale of freezeout transients in the space-charge regions of silicon devices, to the analysis and suppression of delayed turn-off in MOS transistors with compensated channel, and to the temperature dependence of three-dimensional effects in short-channel, narrow-channel MOSFETs.

Dynamic Simulation Analysis of the Crane Hoisting Process Based on Adams

2014 ◽  
Vol 940 ◽  
pp. 132-135 ◽  
Author(s):  
Yi Fan Zhao ◽  
Ling Sha ◽  
Yi Zhu
Keyword(s):  
Dynamic Simulation ◽  
Simulation Analysis ◽  
Three Dimensional ◽  
Wire Rope ◽  
Dynamics Simulation ◽  
Dimensional Model ◽  
Analysis Model ◽  
Three Dimensional Model ◽  
Adams Software ◽  
Simulation Results

Established the dynamics simulation analysis model of crane hoisting mechanism based on the theory of dynamics in Adams software, and then through the three dimensional model of lifting mechanism dynamics entities, the constraints, load, drive can be added, the motion law can be defined to simulation analysis the change of the force of wire rope, the change of displacement, velocity and acceleration of lifting weight in the lifting process. On the basis of the simulation results, it can make a great improvement for the structure of crane and provide a meaningful theoretical reference for the hoisting machinery innovation design.

Simulation Research of Effect of Salinity Wastewater Discharging Ways on Range of Salt Content Rise Nearby the Outfall

2013 ◽  
Vol 777 ◽  
pp. 440-443
Author(s):  
Yao Chen ◽  
Li Li ◽  
Bai Lu Yang ◽  
Chun Long Li
Keyword(s):  
Salt Concentration ◽  
Single Port ◽  
Numerical Models ◽  
Salt Content ◽  
Three Dimensional ◽  
Simulation Research ◽  
Subcritical Flow ◽  
Simulation Results ◽  
Salinity Wastewater ◽  
Better Than

In order to study the effect of salinity wastewater discharging ways on the range of salt content rise nearby the outfall. Two three-dimensional numerical models of discharging ways which were single-port submerged-type and double-port submerged-type in the condition of subcritical flow were researched based on FLUENT. The range of salt content rise of the two discharging ways could be concluded according to the simulation results. The value of maximum salt concentration and average salt concentration of two discharging ways were compared and analyzed. The results showed that double-port submerged-type discharging way was better than single-port submerged-type discharging way.

3D Simulation of Tunnel Collapse Consolidation and In Situ Monitoring Analysis

2011 ◽  
Vol 243-249 ◽  
pp. 3551-3555
Author(s):  
Zhi Min Chen ◽  
De An Zhao
Keyword(s):  
Numerical Models ◽  
Three Dimensional ◽  
In Situ Monitoring ◽  
3D Simulation ◽  
Actual Situation ◽  
Consolidation Effect ◽  
Tunnel Collapse ◽  
Simulation Results ◽  
Shallow Buried Tunnel

A shallow buried tunnel was collapsed during construction. According to the actual situation of the tunnel, different collapse consolidation schemes were put forward and corresponding three-dimensional finite difference numerical models were established and analyzed using FLAC3D software. Base on the 3D Simulation results, a collapse consolidation scheme was determined and constructed. The in-situ monitoring results of vault subsidence and convergence displacement were consistent approximately with the 3D Simulation results. The in-situ measured results were in line with the specification’s allowance and show that the consolidation effect of reinforced concrete casing arch and ahead grouting method is good. This could be referenced for similar engineering.

AVALANCHE DYNAMICS OF THE FINANCIAL MARKET

2005 ◽  
Vol 01 (02) ◽  
pp. 275-283 ◽  
Author(s):  
PEI-LING ZHOU ◽  
CHUN-XIA YANG ◽  
TAO ZHOU ◽  
MIN XU ◽  
JUN LIU ◽  
...  
Keyword(s):  
Stock Market ◽  
Interaction Parameter ◽  
Financial Market ◽  
Real Life ◽  
Percolation Model ◽  
Dynamics Simulation ◽  
Herd Behavior ◽  
The Real ◽  
Avalanche Dynamics ◽  
Simulation Results

A parsimonious percolation model for stock market is proposed, of which the avalanche dynamics agree with the real-life one as well. We have also investigated how the interaction parameter p affects the price dynamics. Simulation results about the formation of the bullish/bearish market and corresponding avalanche taking place in the market indicate that the magnified "herd behavior" resulting from the evolution of p may be the origin of the observed avalanche phenomena.

Modeling and analytical methods for a mounting system with double stage isolation

2021 ◽  
pp. 095440702110632
Author(s):  
Yawei Zheng ◽  
Wen-Bin Shangguan ◽  
Yingzi Kang
Keyword(s):  
Free Vibration ◽  
Rigid Body ◽  
Motion Control ◽  
Three Dimensional ◽  
Vibration Equation ◽  
Proposed Model ◽  
Solution Methods ◽  
Rigid Body Modes ◽  
Simulation Results ◽  
Solutions Of Equations

A calculation method for obtaining the displacements and rigid body modes of a Powertrain Mounting System (PMS) with double stage isolation is proposed in this paper. Firstly, the PMS with double stage isolation is modeled as a 12 Degree of Freedoms (DOFs) model, which includes six DOFs for the powertrain and the subframe respectively. The mounts are simplified as a three-dimensional spring along each axis of its Local Mount Coordinate System (LMCS), which takes the non-linear relation of the force versus the displacement of each spring into account. Secondly, the quasi-static equilibrium equation and the free vibration equation as well as the forced vibration equation of the proposed model are derived and the solutions of equations are presented. Then, the calculation and solution methods are validated by the simulation results. The differences of rigid body modes and displacements of the powertrain between single and double stage isolation are estimated, which demonstrates that the proposed model is more accurate, especially when powertrain mounts are stiff. Also, the effect of locations for powertrain mounts on car body is investigated, which shows that is beneficial for motion control of powertrain.

Analysis of a Control Valve's Inner Flow Field Characteristics Based on CFD

2013 ◽  
Vol 756-759 ◽  
pp. 4652-4655
Author(s):  
Liang Wang
Keyword(s):  
Flow Field ◽  
Energy Loss ◽  
Three Dimensional ◽  
Control Valve ◽  
Flow Path ◽  
Dynamics Simulation ◽  
Flow Field Characteristics ◽  
Simulation Results

In this paper, the inner flow field characteristics of a control valve were analysed through dynamics simulation and showed by using the three-dimensional visualization. Through the analysis of simulation results, reasons were found for the energy loss, which was, then, reduced by the optimized flow path. Calculations about the optimized positions were carried out, the results of which showed an improvement of flow and a significant decrease in energy loss.

Modelling lithosphere dynamics with robust rheological implementations: Towards 3D

2020 ◽  
Author(s):  
Thibault Duretz ◽  
René de Borst ◽  
Ludovic Räss
Keyword(s):  
Numerical Models ◽  
Three Dimensional ◽  
Two Dimensions ◽  
Strain Localisation ◽  
Lithospheric Deformation ◽  
Robust Solution ◽  
Solution Methods ◽  
Graphical Processing ◽  
Three Dimensional Models ◽  
Lithosphere Dynamics

<div>Reliable numerical models of lithospheric deformation require robust solution methods. The latter should account for a complex and realistic rheological model and should also provide convergent and reproducible results.</div><div>Here we present models of crustal-scale deformation that accurately capture the phenomenon of strain localisation in two-dimensions. The use of viscous regularisation yields convergent numerical results. We will compare linearisation methods (consistent tangent, effective viscosity) and discuss the implementation of rheological models (power-law viscous, hardening/softening laws). We will also present three-dimensional models of crustal-scale strain localisation that benefit from both the above-described methods and the computing power of graphical processing units (GPUs).</div>

scholarly journals Hydrodynamic modelling of a regulated Mediterranean coastal lagoon, the Albufera of Valencia (Spain)

2014 ◽  
Vol 16 (5) ◽  
pp. 1062-1076 ◽  
Author(s):  
Javier García Alba ◽  
Aina G. Gómez ◽  
Pilar del Barrio Fernández ◽  
Andrés García Gómez ◽  
César Álvarez Díaz
Keyword(s):  
Coastal Lagoon ◽  
Sea Water ◽  
Numerical Models ◽  
Coastal Lagoons ◽  
Three Dimensional ◽  
Real Data ◽  
Two Dimensional ◽  
Shallow Water Models ◽  
Dimensional Models

Coastal lagoon hydrodynamics are strongly influenced by sea water exchange, especially when the connection between the lagoon and the sea is artificially regulated. These situations increase the complexity of the hydrodynamic regime, requiring the use of numerical models to understand their behaviour. Traditionally, one-dimensional models have been used, although in recent years, the development of two-dimensional shallow water models and advanced numerical techniques have increased notably. However, most of the existing bi-dimensional models consider the connection to the sea as a boundary condition, and they do not take into consideration the sea-lagoon exchange. In this paper, a fully two-dimensional hydrodynamic model of a heavily regulated coastal lagoon, which includes the artificial connection with the sea, is presented. The model allows the characterization of water level variation in the lagoon, taking into account the combined effect of different forcings. This model consists of two hydrodynamic modules: a long wave module (two-dimensional depth-averaged) which includes the analysis of a system of sluice gates, and a wind module (quasi three-dimensional). The model was successfully calibrated and validated with real data, showing its ability to accurately describe the hydraulic dynamics of regulated coastal lagoons.

Three-dimensional computational fluid dynamics simulation of valve-induced water hammer

2016 ◽  
Vol 231 (12) ◽  
pp. 2263-2274 ◽  
Author(s):  
Shuai Yang ◽  
Dazhuan Wu ◽  
Zhounian Lai ◽  
Tao Du
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Method Of Characteristics ◽  
Three Dimensional ◽  
Water Hammer ◽  
Dynamics Simulation ◽  
Computational Fluid Dynamics Simulation ◽  
Time Step ◽  
Obvious Effect ◽  
Simulation Results

In this study, three-dimensional computational fluid dynamics simulation was adopted to evaluate the valve-induced water hammer phenomena in a typical tank-pipeline-valve-tank system. Meanwhile, one-dimensional analysis based on method of characteristics was also used for comparison and reference. As for the computational fluid dynamics model, the water hammer event was successfully simulated by using the sliding mesh technology and considering water compressibility. The key factors affecting simulation results were investigated in detail. It is found that the size of time step has an obvious effect on the attenuation of the wave and there exists a best time step. The obtained simulation results have a good agreement with the experimental data, which shows an unquestionable advantage over the method of characteristics calculation in predicting valve-induced water hammer. In addition, the computational fluid dynamics simulation can also provide a visualization of the pressure and flow evolutions during the transient process.

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