Nonlinear Physics Lab


Animations for:
Mono-layer Granular Flows
-------- Rolling Spheres on a Smooth Incline   

Spherical steel beads are flowing through a 2D channel that is bounded by rough sidewalls. Inclination angle q = 1 ~ 4 degrees;  d = diameter of the spheres = 0.3175cm.  

MPEG Movies of Typical Flows :

Oscillatory Two-phase Flow (2PF):[(5.1Mb)] ~8.7sec. in experiment; channel width = 6d.
plus [Preview(95kb)], [3X fast forward (~6.7sec, 1.3Mb)], [6X fast forward(~6.7 sec,0.7Mb)], [Reverse(~2.2sec, 1.3Mb)] .

Uniform Dense Flow (UDF):[(5.1Mb) ~8.7sec. in experiment; channel width = 12d.
          plus [Preview (94kb)], [3X fast forward(~6.7sec, 1.3Mb)], [Reverse (~2.2sec, 1.3Mb)].

Local close-up views of UDF   (Channel width = 12d)
(1) near the rough boundary (shear band):[ (2.6Mb) , (2.6Mb) ], [Preview(291kb)]
* Beads seen at the bottom edge of the images belong to the layer closest to a bumpy wall. 
-- out-of-focus images, total length =(4/1000)sec/fr.*260fr.
(2) along the centerline of the channel (plug region):[ (2.6Mb) ], [Preview(291kb)]
       -- same image conditions as in (1)
(3) with ultra-high resolution:[ (5.7Mb) ]
       -- 3000 frames/sec. , 1250 frames in total ; particle-wise spatial resolution 

Accelerating Gaseous Flow (AGF):[(5.1Mb)] ~2.2sec. in experiment; channel width = 16d
          plus [Preview (375kb)], [Reverse(~0.56sec, 1.3Mb)] .. 
    * In the movies above, the left edge of the image coincides the inlet of the channel. 
    * See another region starting at  ~25d away from the channel inlet [( 5.1Mb )]  for comparison.

Flow around an Obstacle [(1.3Mb)~4.6sec. in experiment; obstacle diameter = 3.5d
plus [3X fast forward (386kb)], [2X fast forward(~3.0sec ,375kb)], [Reverse (1.3Mb)]

-- email: JC Tsai --