Thoughts

User Tools

Site Tools

Trace:
dustdevils

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revisionPrevious revision
Next revision		Previous revision
dustdevils [2025/03/31 16:07] – admindustdevils [2025/04/12 19:29] (current) – admin
Line 1: Line 1:
-==== Dustdevils redux ====+===== Dust devils redux: using numerical python =====
  
  
-This page shows a revisit to {{ :dustdevils:fiedlerkanak2001.pdf | Rayleigh-BeÂnard convection as a tool for studying dust devils}}, but with the computations done with numerical python.+This page shows a revisit to {{ :dustdevils:fiedlerkanak2001.pdf | Rayleigh-Benard convection as a tool for studying dust devils}}, but with the computations done with numerical python.   
 +It is a substantial upgrade to [[https://12characters.net/dustdevil/ |my old dust devil page]].
  
 To reproduce these simulations, you may use my ipython notebook: To reproduce these simulations, you may use my ipython notebook:
-[[https://github.com/bfiedler/metr4323/blob/main/N140_convection3d.ipynb|3D convection, periodic]] +[[https://github.com/bfiedler/metr4323/blob/main/N140_convection3d.ipynb|3D convection, periodic]]. 
-In cell number 28, set ''nexp'' to 91:+ 
 +To reproduce the visualizations, you will need {{https://github.com/bfiedler/dustdevils/blob/main/dustdevils.tar.gz | my companion python programs}}. 
 + 
 +In the notebook, in cell number 28, set ''nexp'' to 91:
 <code> <code>
 # choose an integer, see choices for nexp below # choose an integer, see choices for nexp below
Line 32: Line 36:
 If you then select 'Run All Cells" for the ipython notebook, the simulation will be complete If you then select 'Run All Cells" for the ipython notebook, the simulation will be complete
 in about 20 minutes (with my i7 chip).  But the simulation for the images here was with the  in about 20 minutes (with my i7 chip).  But the simulation for the images here was with the 
-hi-resolution, or ''Nx,Ny,Nz= 129,129,33''. With those specs, the simulation may need 5 hours.+hi-resolution, or ''Nx,Ny,Nz= 129,129,33''. With those specs, the simulation may need 5 hours (and 9 GB of disk space).
  
 In cell 30, the buoyancy is initialized with  In cell 30, the buoyancy is initialized with 
Line 39: Line 43:
      + .00001*np.cos(6*np.pi*xb/xmax - 2*np.pi*yb/ymax)      + .00001*np.cos(6*np.pi*xb/xmax - 2*np.pi*yb/ymax)
 </code> </code>
-I am not sure why that that is apparently different from the idealized choices in Fiedler and Kanak, +I am not sure why that is apparently different from the idealized choices in Fiedler and Kanak, 
-but it makes the point about **symmetry breaking**.+but it makes the point about //symmetry breaking// needed to produce the vertical vorticity of the extreme 
 +events, which are akin to dust devils. 
 + 
 + 
 +==== time history of extremes ==== 
 + 
 +Try  
 +<code> 
 +./hist.py R4096g0w4 1 400 
 +</code> 
 +if all went okay, 
 +<code> 
 +./hist.py R4096g0w4 1 40 > R4096g0w4.hist 
 +</code>0 
 + 
 +And then  
 +<code> 
 +./plothist.py -s R4096g0w4.hist  
 +</code>  
 + 
 +That should produce the following image, which shows a dust devil event just prior to t=30.
  
  
-=== time history of extremes === 
 ^{{ :dustdevils:r4096g0w4.png?700 }}^ ^{{ :dustdevils:r4096g0w4.png?700 }}^
 | some extreme values at the surface | | some extreme values at the surface |
  
-=== vertical vorticity at the lowest level ===+ 
 +==== vertical vorticity at the lowest level ==== 
 +<code> 
 +mkdir pngs 
 +./npy2contour.py -o pngs R4096g0w4 000001 000400 
 +./maketitle.py -o titleh.png 
 +./png2mp4.py pngs/0 -t titleh.png 
 +</code> 
 + 
 +That will produce ''video.mp4'', showing twin dust devils peaking at t=29.8:
  
 {{ :dustdevils:wzeta.mp4 |}} {{ :dustdevils:wzeta.mp4 |}}
  
-=== isosurface animation ===+==== isosurface animation ====
  
-The extreme event (a.k.a. dustdevil).+The extreme event (a.k.a. dust devils) in 3-D, with isosurfaces. 
 + 
 +<code> 
 +mkdir vista 
 +./npy2vista.py  R4096g0w4 000270 000320 -o vista 
 +./maketitlevista.py 
 +./png2mp4.py vista/0 -t titlevista.png 
 +</code>
  
 {{ :dustdevils:pzeta.mp4 |}} {{ :dustdevils:pzeta.mp4 |}}
  
-=== Some interactive images at $t=29.8$ ===+==== Some interactive images at $t=29.8$ ==== 
 + 
 +<code> 
 +./npy2vista.py -s R4096g0w4 000298 
 +open scene.html 
 +</code> 
 Use your mouse, have fun ... Use your mouse, have fun ...
  
 {{url>https://12characters.net/rbdd/t298zm40pm2.html}} {{url>https://12characters.net/rbdd/t298zm40pm2.html}}
 $\zeta=-40$ (purple)   , $p=-2$ (green), and $s$ at the surface $\zeta=-40$ (purple)   , $p=-2$ (green), and $s$ at the surface
 +
 +I did not finish implementing the command line options for ''npy2vista.py'',
 +but the source code can be easily edited to select the desired isosurfaces.
 +(You may want to copy ''npy2vista.py'' to a file of some other name, and edit that...)
 +
 +Change these lines:
 +<code>
 +#    plotter.add_mesh(contours_w_neg, color="lightblue", opacity=0.5, label="w = -0.5")
 +#    plotter.add_mesh(contours_w_pos, color="green", opacity=0.5, label="w = 0.5")
 +    plotter.add_mesh(contours_p1, color="green", opacity=0.5, label="p = -2")
 +#    plotter.add_mesh(contours_p2, color="purple", opacity=1.0, label="p = -3")
 +#    plotter.add_mesh(contours_p3, color="yellow", opacity=.5, label="s =  2")
 +#    plotter.add_mesh(contours_p4, color="red", opacity=.5, label="c =  6")
 +    plotter.add_mesh(contours_p5, color="purple", opacity=.5, label="$\zeta$ =  -40")
 +    plotter.add_mesh(edges, color='black', line_width=3, label="Domain Boundaries")
 +    plotter.add_mesh(origin_marker, color="yellow", label="Origin Marker")
 +    plotter.add_text(time,color='pink')
 +#    plotter.add_mesh(contour_2d, cmap="coolwarm", opacity=0.8, label="2D Contour (p at z=0)")
 +    plotter.add_mesh(slice_plane, scalars="s", cmap="OrRd", opacity=1.0, clim=[0,3.0 ])
 +</code>
 +to
 +<code>
 +    plotter.add_mesh(contours_w_neg, color="lightblue", opacity=0.5, label="w = -0.5")
 +    plotter.add_mesh(contours_w_pos, color="green", opacity=0.5, label="w = 0.5")
 +#    plotter.add_mesh(contours_p1, color="green", opacity=0.5, label="p = -2")
 +#    plotter.add_mesh(contours_p2, color="purple", opacity=1.0, label="p = -3")
 +#    plotter.add_mesh(contours_p3, color="yellow", opacity=.5, label="s =  2")
 +    plotter.add_mesh(contours_p4, color="red", opacity=.5, label="c =  6")
 +    plotter.add_mesh(contours_p5, color="purple", opacity=.5, label="$\zeta$ =  -40")
 +    plotter.add_mesh(edges, color='black', line_width=3, label="Domain Boundaries")
 +    plotter.add_mesh(origin_marker, color="yellow", label="Origin Marker")
 +    plotter.add_text(time,color='pink')
 +#    plotter.add_mesh(contour_2d, cmap="coolwarm", opacity=0.8, label="2D Contour (p at z=0)")
 +    plotter.add_mesh(slice_plane, scalars="s", cmap="OrRd", opacity=1.0, clim=[0,3.0 ])
 +</code>
 +
 +And again:
 +
 +<code>
 +./npy2vista.py -s R4096g0w4 000298
 +open scene.html
 +</code>
  
 {{url>https://12characters.net/rbdd/t298wpm5c6.html}} {{url>https://12characters.net/rbdd/t298wpm5c6.html}}
 $w=.5$ (green), $w=-.5$ (grey) , $c=6$ (red) $w=.5$ (green), $w=-.5$ (grey) , $c=6$ (red)
  
 +The suitably renamed ''scene.html'' can then be uploaded to a website, as done here.
dustdevils.1743455259.txt.gz · Last modified: by admin
Donate Powered by PHP Valid HTML5 Valid CSS Driven by DokuWiki