A Three-Dimensional Numerical Model for the Dispersion of Heavy Gases over Complex Terrain

1986 ◽  
pp. 743-756 ◽  
Author(s):  
Yannik J. Riou ◽  
Assaad E. Saab
Keyword(s):  
Numerical Model ◽  
Complex Terrain ◽  
Three Dimensional

Thermodynamic Recovery of the Pressure and Temperature Fields over Complex Terrain Using Wind Fields Derived by Multiple-Doppler Radar Synthesis

2019 ◽  
Vol 147 (10) ◽  
pp. 3843-3857
Author(s):  
Yu-Chieng Liou ◽  
Po-Chien Yang ◽  
Wen-Yuan Wang
Keyword(s):  
Numerical Model ◽  
Cost Function ◽  
Complex Terrain ◽  
Three Dimensional ◽  
Flow Region ◽  
Temperature Fields ◽  
Radiosonde Data ◽  
Squall Line ◽  
Wind Fields ◽  
Retrieval Scheme

Abstract A new thermodynamic retrieval scheme is developed by which one can use the wind fields synthesized from multiple-Doppler radars to derive the three-dimensional thermodynamic fields over complex terrain. A cost function consisting of momentum equations and a simplified thermodynamic equation is formulated. By categorizing the analysis domain into flow and terrain regions, the variational technique is applied to minimize this cost function only within the flow region, leading to the solutions for the three-dimensional pressure and temperature perturbations immediately over terrain. Using idealized datasets generated by a numerical model, an experiment is first conducted to assess the accuracy of the proposed algorithm. The retrieval scheme is then applied to a real case that occurred during the 2008 Southwestern Monsoon Experiment (SoWMEX) conducted in Taiwan. The retrieved thermodynamic fields, verified by radiosonde data, reveal the structure of a prefrontal squall line as it approaches a mountain. The retrieved three-dimensional high-resolution pressure and temperature along with the wind fields not only allow us to better understand the thermodynamic and kinematic structure of a heavy rainfall system, but can also be assimilated into a numerical model to improve the forecast.

A THREE-DIMENSIONAL NUMERICAL MODEL FOR SELECTIVE WITHDRAWAL IN COASTAL AREA

2018 ◽  
Vol 74 (5) ◽  
pp. I_571-I_576
Author(s):  
Yasuo NIIDA ◽  
Norikazu NAKASHIKI ◽  
Takaki TSUBONO ◽  
Shin’ichi SAKAI ◽  
Teruhisa OKADA
Keyword(s):  
Numerical Model ◽  
Coastal Area ◽  
Three Dimensional ◽  
Selective Withdrawal

scholarly journals Blowing and drifting snow in Alpine terrain: numerical simulation and related field measurements

1998 ◽  
Vol 26 ◽  
pp. 174-178 ◽  
Author(s):  
Peter Gauer
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Three Dimensional ◽  
Field Measurements ◽  
Blowing Snow ◽  
Related Field ◽  
Drifting Snow ◽  
Physically Based ◽  
Snow Transport

A physically based numerical model of drifting and blowing snow in three-dimensional terrain is developed. The model includes snow transport by saltation and suspension. As an example, a numerical simulation for an Alpine ridge is presented and compared with field measurements.

Evaluation of a Three-Dimensional Numerical Model of a Scaled Circulating Fluidized Bed

2001 ◽  
Vol 40 (23) ◽  
pp. 5081-5086 ◽  
Author(s):  
Claus H. Ibsen ◽  
Tron Solberg ◽  
Bjørn H. Hjertager
Keyword(s):  
Numerical Model ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Three Dimensional

Three-dimensional numerical model of short-circuiting transfer in GMAW

2020 ◽  
Vol 64 (12) ◽  
pp. 2011-2017
Author(s):  
K. Hashimoto ◽  
Y. Hirata ◽  
K. Kadota ◽  
Y. Ogino
Keyword(s):  
Numerical Model ◽  
Three Dimensional

scholarly journals An energy landscape approach to locomotor transitions in complex 3D terrain

2020 ◽  
Vol 117 (26) ◽  
pp. 14987-14995 ◽  
Author(s):  
Ratan Othayoth ◽  
George Thoms ◽  
Chen Li
Keyword(s):  
Potential Energy ◽  
Complex Terrain ◽  
Statistical Physics ◽  
Energy Landscape ◽  
Three Dimensional ◽  
Single Mode ◽  
Physical Interaction ◽  
Landscape Approach ◽  
3D Terrain ◽  
Potential Energy Landscape

Effective locomotion in nature happens by transitioning across multiple modes (e.g., walk, run, climb). Despite this, far more mechanistic understanding of terrestrial locomotion has been on how to generate and stabilize around near–steady-state movement in a single mode. We still know little about how locomotor transitions emerge from physical interaction with complex terrain. Consequently, robots largely rely on geometric maps to avoid obstacles, not traverse them. Recent studies revealed that locomotor transitions in complex three-dimensional (3D) terrain occur probabilistically via multiple pathways. Here, we show that an energy landscape approach elucidates the underlying physical principles. We discovered that locomotor transitions of animals and robots self-propelled through complex 3D terrain correspond to barrier-crossing transitions on a potential energy landscape. Locomotor modes are attracted to landscape basins separated by potential energy barriers. Kinetic energy fluctuation from oscillatory self-propulsion helps the system stochastically escape from one basin and reach another to make transitions. Escape is more likely toward lower barrier direction. These principles are surprisingly similar to those of near-equilibrium, microscopic systems. Analogous to free-energy landscapes for multipathway protein folding transitions, our energy landscape approach from first principles is the beginning of a statistical physics theory of multipathway locomotor transitions in complex terrain. This will not only help understand how the organization of animal behavior emerges from multiscale interactions between their neural and mechanical systems and the physical environment, but also guide robot design, control, and planning over the large, intractable locomotor-terrain parameter space to generate robust locomotor transitions through the real world.

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