Movie Gallery 1
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Animations contained on this page are examples from different projects that have been carried out by the PALM group at IMUK? in the past. Most sequences have been created with the PArallelized LES Model (PALM) using a distributed virtual reality software system (DSVR) for graphic output. In contrast with other graphic software, DSVR is parallelized and is running embedded in PALM (i.e. no graphic post-processing is done). This method avoids output of raw data (in the order of 10-100 GByte per timestep for large model runs). Instead, only graphic primitives are stored and replayed using streaming server technology. Depending on the available graphic hardware, also stereoscopic views can be created. For further details of DSVR see here. Recently we also started to create movies with NCL and VAPOR. Therefore we will extent this section in near future.
For each animation, a short description of the displayed scene and some general setup information for the respective model run are given.
All visualization data (images, movies) is protected by copyright.
Available movies in Gallery 1:
Convective boundary layer with horizontally homogeneous heating
The following four sequences are showing different flow aspects and phenomena of the convective boundary layer. All simulations are driven by a constant and horizontally homogeneous surface sensible (and latent) heat flux. The initial state is an atmosphere at rest with neutral stratification, capped by an inversion at about 800m. Simulations differ in domain size and grid resolution.
| First sequence: 3D view on moist convection (2001)
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Project: none
Responsible: Siegfried Raasch?
Description: Particles are released near the surface. The particle color reflects the buoyancy at the current particle position (red: positive, blue: negative). The particle size is proportional to the magnitude of the vertical velocity component. The isososurfaces display areas with a liquid water content larger than 0.2 g/kg, i.e. cumulus clouds. The horizontal domain size in this simulation is too small in order to allow the development of the typical near-surface hexagonal flow pattern (see next two sequences).
| Model Setup
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| Total domain size (x|y|z): | 2000m x 2000m x 4638m
| | Grid spacing (x|y|z): | 25m x 25m x 25m
| | Number of grid points (x|y|z): | 80 x 80 x 80
| | Simulated time: | 1h
| | CPU-time: | 176h
| | Number of CPUs: | 32
| | Machine/ processor type: | SGI Altix ICE at HLRN / Intel Xeon Gainestown
| | Visualization software: | DSVR
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| Video Format | File size
| | Flash (.flv) | 9.6mb | Download
| | MPEG (.avi) | 9.7mb | Download
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| Fourth sequence: dust devils (2006)
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Project: LES of dust devils
Responsible: Theres Riechelmann?
Description:
This animation displays 3d-views of the lower 150m of the same convective boundary layer as shown before. Particles are released near the surface in those areas, where the dynamic pressure is below a specified threshold of -2 Pa. This allows to visualize dust-devil like vortices, which always have a pressure minimum in their center. The particle color displays the magnitude of horizontal velocity (red: fast, blue: slow). At the end of the sequence, two dust devils with opposite rotation collide and cancel out each other due to conservation of angular momentum.
| Model Setup
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| Total domain size (x|y|z): | 768m x 768m x 768m
| | Grid spacing (x|y|z): | 2m x 2m x 2m
| | Number of grid points (x|y|z): | 384 x 384 x 384
| | Simulated time: | 1h
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| | Number of CPUs: |
| | Machine/ processor type: | IBM Regatta / Power 4
| | Visualization software: | DSVR
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| Video Format | File size
| | Flash (.flv) | 9.6mb | Download
| | MPEG (.avi) | 9.7mb | Download
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| Fifth sequence: structure parameter for temperature CT2 (2010)
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Project: High-resolution LES studies of the turbulent structure of the lower atmospheric boundary layer over heterogeneous terrain and implications for the interpretation of scintillometer data
Responsible: Björn Maronga?
Description:
This visualization shows the turbulent structure parameter CT2 in the surface layer of a convectively driven boundary layer. Dark colors match to high values up to 0.01, whereas white colors represent lower values down to 0.001. All values which are out of range are set to transparent. Shown is the last half an hour of the simulation. The movie shows, that CT2 is high near the surface, decreasing with height. High values, in comparison with their horizontal environment can be observed in regions where warm air rises upward (plumes). These regions organize in hexagonal cells, which can also be seen in this sequence. Please note that the capping inversion in this simulation was in a height of about 400m.
| Model Setup
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| Total domain size (x|y|z): | 1280m x 1280m x 1080m
| | Grid spacing (x|y|z): | 5m x 5m x 5m
| | Number of grid points (x|y|z): | 256 x 256 x 256
| | Simulated time: | 1.5h
| | CPU-time: | 1.5h
| | Number of CPUs: | 64
| | Machine/ processor type: | SGI Altix ICE at HLRN / Intel Xeon Gainestown
| | Visualization software: | VAPOR
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Kármán vortex street (2009)
Flow over an ice lead (2006)
| Flow over an ice lead (2006)
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Project: The Physics of turbulence over Antarctic leads and polynyas and its parameterization: a joint study using observations, LES and a micro-/mesoscale model
Responsible: Björn Witha?
Description:
Leads in sea ice are responsible for most of the latent and sensible heat transfer from ocean to atmosphere within the marginal ice zones. The animation displays a flow along x (from left to right with a geostrophic wind of about 3 m/s) from sea ice over a lead of 1000m width. The incoming flow is laminar (without turbulence), neutrally stratified, and capped by an inversion above 300m. The surface temperature of ice is assumed to be -23.3C, while the open sea water has a temperature near the freezing point of about -3C. Particles are released near the surface and closely below the inversion. The particle color reflects the buoyancy at the current particle position (red: positive, blue: negative). The particle size is proportional to the magnitude of the vertical velocity component. Cyclic boundary conditions along y are assumed. Convection is generated above the lead but the flow re-stratifies soon after passing the lead. The spatial resolution of the model is still insufficient to resolve the turbulent convection above the first half (upstream part) of the lead.
| Model Setup
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| Total domain size (x|y|z): | 5760m x 1280m x 1477m
| | Grid spacing (x|y|z): | 10m x 10m x 10m
| | Number of grid points (x|y|z): | 576 x 128 x 66
| | Simulated time: | 45min
| | CPU-time: | 2600s
| | Number of CPUs: | 32
| | Machine/ processor type: | IBM-Regatta / Power4
| | Visualization software: | DSVR
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| Download
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| Video Format | File size
| | Flash (.flv) | 7.5mb | Download
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Flow around a single cube (2005)
LES of a city quarter of Hanover (Allianz tower, 2006)
| Allianz tower (2006)
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Project: none
Responsible: Siegfried Raasch?
Description:
Turbulent flow around a city quarter of Hannover. The mean flow is from west (right) with a speed of 1 m/s (neutral stratification is assumed). Clouds of particles are periodically released in front of the large building (Allianz tower) and in the courtyard of another complex of buildings. The particle color reflects the height above ground (red: high, blue: low). Topography data are from laser altimeter measurements (kindly provided by the Institut für Kartographie und Geoinformatik, Leibniz Universität Hannover). The resolution of the laser data allows to resolve cars on the street west of the Allianz building, staying there because of a red traffic light. The sequence shows that the turbulent flow within street canyons is highly variable so that flow directions may change completely within short times.
| Model Setup
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| Total domain size (x|y|z): | 256m x 256m x 200m
| | Grid spacing (x|y|z): | 1m x 1m x 1m
| | Number of grid points (x|y|z): | 256 x 256 x 200
| | Simulated time: | 1h
| | CPU-time: | 1800s
| | Number of CPUs: | 32
| | Machine/ processor type: | IBM-Regatta / Power4
| | Visualization software: | DSVR
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| Download
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| Video Format | File size
| | Flash (.flv) | 8.3mb | Download
| | MPEG (.avi) | 8.3mb | Download
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Mixing in the entrainment zone (2010)
LES of cumulus clouds (2012)
| Cumulus clouds (2012)
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Project: Investigations on in-cloud turbulence effects on drop growth and precipitation formation
Responsible: Theres Riechelmann?, Björn Maronga?
Description:
This animation shows the development of cumulus clouds at an accelerated pace in the homogeneously-heated convective boundary layer. The shown time period spans approx. 80 minutes, the shown region is of size 1.4 km x 1.4 km in the horizonzal and 1.5 km in the vertical direction. The clouds are represented through the liquid water content. Darker (gray) shades refer to a higher water content than white shades. The background scenary here is not physical and used for decorational reasons only.
| Model Setup
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| Total domain size (x|y|z): | 4096m x 4096m x 1900m
| | Grid spacing (x|y|z): | 4m x 4m x 4m
| | Number of grid points (x|y|z): | 1024 x 1024 x 448
| | Simulated time: | 2h
| | CPU-time: | 6.5h
| | Number of CPUs: | 1024
| | Machine/ processor type: | SGI Altix ICE at HLRN
| | Visualization software: | VAPOR
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| Download
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| Video Format | File size
| | Flash (.flv) | 3.9mb | Download
| | MPEG (.avi) | 3.6mb | Download
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