Grid Nesting with STWAVE

2002 ◽  
Author(s):  
Jane M. Smith ◽  
S. J. Smith
Keyword(s):  
Grid Nesting

scholarly journals Objective evaluation of mesoscale simulations of the Algiers 2001 flash flood by the model-to-satellite approach

2006 ◽  
Vol 7 ◽  
pp. 247-250 ◽  
Author(s):  
N. Söhne ◽  
J.-P. Chaboureau ◽  
S. Argence ◽  
D. Lambert ◽  
E. Richard
Keyword(s):  
Radiative Transfer ◽  
Flash Flood ◽  
Objective Evaluation ◽  
Brightness Temperatures ◽  
Grid Nesting ◽  
Mesoscale Simulations

Abstract. An objective evaluation of mesoscale simulations by the model-to-satellite approach is performed. The model-to-satellite approach consists in calculating brightness temperatures (BT) from model variables with a radiative transfer code. It allows to compare directly and quantitatively simulations and observations by calculating statistical scores. This method is detailed and used herein to objectively evaluate an ensemble of Meso-NH simulations of the Algiers 2001 flash flood. In particular, the improvement due to the grid-nesting is shown.

scholarly journals Multi‐Grid Nesting Ability to Represent Convections Across the Gray Zone

2019 ◽  
Vol 11 (12) ◽  
pp. 4352-4376 ◽  
Author(s):  
Xin‐Zhong Liang ◽  
Qi Li ◽  
Haixia Mei ◽  
Mingjian Zeng
Keyword(s):  
Gray Zone ◽  
Grid Nesting

scholarly journals Numerical Study of the 10 January 1998 Lake-Effect Bands Observed during Lake-ICE

2005 ◽  
Vol 62 (9) ◽  
pp. 3232-3249 ◽  
Author(s):  
Gregory J. Tripoli
Keyword(s):  
Lake Michigan ◽  
Numerical Study ◽  
Real Data ◽  
Streamwise Vorticity ◽  
Lake Ice ◽  
Fine Grid ◽  
Near Surface ◽  
Wave Trapping ◽  
Initial Location ◽  
Grid Nesting

Abstract This paper presents the results of a series of idealized cloud resolving simulations of the evolution of moist roll convection observed as part of the Lake-Induced Convection Experiment (Lake-ICE) that took place during the 1997/98 winter over central Lake Michigan. Satellite and radar observations of the roll convection depict striking linear rolls stretching from 10 km off the western shore of the lake, across to the eastern shore, and then continuing across Michigan. The spacing of the primary rolls was observed to be 6 km, giving a ratio of spacing to depth of about 5:1, which is consistent with theory. In addition, a longer wavelength (13 km) of stationary banding was observed parallel to the shoreline. In an earlier study of this case, multiply nested simulations of the convective rolls based on real data variable initialization were successful in producing banded structures with similar spacing and location over the water to those observed using fine grid resolution of about 500 m. Unfortunately, the initial locations of simulated bands were organized primarily by numerical effects of grid interpolation. This suggested that the spacing of the bands was robust, but that their initial location was highly sensitive to subtle systematic forcings. In this paper, a set of idealized model experiments, designed to isolate the role that physically realistic local forcing plays in the organization of the rolls, was performed. Because externally generated upstream turbulence was suppressed in these tests so as not to bias the result, the generation of rolls was delayed until 20–30 km downwind of the observed location and the location simulated in the previous grid nesting experiments. It was shown that the subtle effects of the shoreline geometry were sufficient to spawn a near-surface streamwise vorticity that became the primary seed for roll development at the most efficient mode of roll convection. These results suggest that previous structures evolved in the upstream shear-driven land-based mixed layer were likely also important in determining where the nonlocal overturning was first triggered. It is not clear from these results whether the shear-driven structures that evolved over the land also played a significant role in organizing the structural geometry of the lake rolls. Results also suggested that the shore parallel bands were a robust feature of the atmospheric structure resulting from resonant gravity wave trapping in the frontal layer.

scholarly journals Integer Programming Formulations for Approximate Packing Circles in a Rectangular Container

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Igor Litvinchev ◽  
Edith Lucero Ozuna Espinosa
Keyword(s):  
Large Scale ◽  
Optimization Problem ◽  
Continuous Optimization ◽  
Packing Problem ◽  
Regular Grid ◽  
Food Industries ◽  
Rectangular Container ◽  
Binary Problem ◽  
Weighted Number ◽  
Grid Nesting

A problem of packing a limited number of unequal circles in a fixed size rectangular container is considered. The aim is to maximize the (weighted) number of circles placed into the container or minimize the waste. This problem has numerous applications in logistics, including production and packing for the textile, apparel, naval, automobile, aerospace, and food industries. Frequently the problem is formulated as a nonconvex continuous optimization problem which is solved by heuristic techniques combined with local search procedures. New formulations are proposed for approximate solution of packing problem. The container is approximated by a regular grid and the nodes of the grid are considered as potential positions for assigning centers of the circles. The packing problem is then stated as a large scale linear 0-1 optimization problem. The binary variables represent the assignment of centers to the nodes of the grid. Nesting circles inside one another is also considered. The resulting binary problem is then solved by commercial software. Numerical results are presented to demonstrate the efficiency of the proposed approach and compared with known results.

Application of Grid-Nesting Technique on Sandwaves Migration Simulation II- Sandwaves Migration in Northern South China Sea

2014 ◽  
Vol 57 (3) ◽  
pp. 355-368 ◽  
Author(s):  
JIANG Wen-Bin ◽  
LIN Mian ◽  
LI Yong ◽  
FAN Feng-Xin ◽  
YAN Jun
Keyword(s):  
South China Sea ◽  
South China ◽  
Northern South China Sea ◽  
China Sea ◽  
Grid Nesting

A grid nesting method for large-eddy simulation of planetary boundary-layer flows

1996 ◽  
Vol 80 (1-2) ◽  
pp. 167-202 ◽  
Author(s):  
Peter P. Sullivan ◽  
James C. McWilliams ◽  
Chin-Hoh Moeng
Keyword(s):  
Boundary Layer ◽  
Large Eddy Simulation ◽  
Planetary Boundary Layer ◽  
Boundary Layer Flows ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Grid Nesting

High-Resolution Non-Hydrostatic Simulations of Flash-Flood Episodes with Grid-Nesting and Ice-Phase Parameterization

2000 ◽  
Vol 72 (2-4) ◽  
pp. 203-221 ◽  
Author(s):  
J. Stein ◽  
E. Richard ◽  
J. P. Lafore ◽  
J. P. Pinty ◽  
N. Asencio ◽  
...  
Keyword(s):  
High Resolution ◽  
Flash Flood ◽  
Grid Nesting ◽  
Ice Phase

scholarly journals Evaluation of the dynamic core of the PALM model system 6.0 in a neutrally stratified urban environment: comparison between LES and wind-tunnel experiments

2021 ◽  
Vol 14 (6) ◽  
pp. 3317-3333
Author(s):  
Tobias Gronemeier ◽  
Kerstin Surm ◽  
Frank Harms ◽  
Bernd Leitl ◽  
Björn Maronga ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Model System ◽  
Immersed Boundary ◽  
Wind Tunnel Experiments ◽  
Building Geometry ◽  
Wind Tunnel Measurements ◽  
Mean Wind Speed ◽  
Simulation Results ◽  
Grid Nesting ◽  
Neutrally Stratified

Abstract. We demonstrate the capability of the PALM model system version 6.0 to simulate neutrally stratified urban boundary layers. Our simulation uses the real-world building configuration of the HafenCity area in Hamburg, Germany. Using PALM's virtual measurement module, we compare simulation results to wind-tunnel measurements of a downscaled replica of the study area. Wind-tunnel measurements of mean wind speed agree within 5 % on average while the wind direction deviates by approximately 4∘. Turbulence statistics similarly agree. However, larger differences between measurements and simulation arise in the vicinity of surfaces where building geometry is insufficiently resolved. We discuss how to minimize these differences by improving the grid layout and give tips for setup preparation. Also, we discuss how existing and upcoming features of PALM like the grid nesting and immersed boundary condition help improve the simulation results.

scholarly journals Modelling Airport Pollutants Dispersion at High Resolution

2017 ◽  
Author(s):  
Claire Sarrat ◽  
Sébastien Aubry ◽  
Thomas Chaboud ◽  
Christine Lac
Keyword(s):  
Air Quality ◽  
Real Data ◽  
Atmospheric Model ◽  
Air Traffic ◽  
Physical Models ◽  
Transport Systems ◽  
Aircraft Emissions ◽  
Time Step ◽  
Preliminary Study ◽  
Grid Nesting

Local air quality is a major concern for the population regularly exposed to high levels of air pollution. The airport, mainly due to its aircraft engines activities during taxiing and take off, is often submitted to heterogeneous but important concentrations of NOx and PM. The study suggests an innovative approach to determine the air traffic impact on air quality at the scale of the airport, its runways and terminals, in order to be able to locate the persistent high concentrations spots. The pollutants concentrations at 10 m resolution and 1 s time step are calculated in order to identify the most affected areas of an airport platform. A real day of air traffic on a regional airport is simulated, using real data as aircraft trajectories (from radar streams). In order to estimate the aircraft emissions, the Air Transport Systems Evaluation Infrastructure (IESTA) is used. Regarding local air quality, IESTA relies on the non-hydrostatic meso-scale atmospheric model Meso-NH using grid-nesting capabilities with 3 domains, for this study. The detailed cartography of the airport distinguishes between grassland, parking and terminals, allowing to compute exchanges of heat, water and momentum between the different types of surfaces and the atmosphere as well as the interactions with the building using a drag force. The dynamic parameters like wind, temperature, turbulent kinetic energy and pollutants concentration are computed at 10 m resolution over the 2 × 4 km airport domain. The pollutants are considered in this preliminary study as passive tracers, without chemical reactions. This preliminary study aims at proving the feasibility of high scale modelling over an airport with state of the art physical models.

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