Other research interests. - My main home page
 Duke Physics |
 CNCS |
|---|
This is a space-time plot of a sandpile sinusoidally driven in the vertical direction at approximately 10 Hz with an amplitude of 3.08 mm. The cell itself is completely level -- within 0.5% verified by direct measurement. The granular material is the ``rough sand'' which is 0.613 mm in diameter.
The dimensionless acceleration \Gamma= a \omega2 g-1 = 1.18 (G=a w2 g-1, if your browser understands the face tag...)
The picture axes are as follows: horizontal position within the cell goes across the picture from left to right and the scale is 0-14 cm; time goes from top to bottom, each line representing another time step from t=0 min to 150 min (2 ½ hours)
The intensity at each space-time location is a measure of the height of the sandpile at that particular time, scaled to occupy the full color scale. Dark blues correspond to a valley and reds are the peak of the sandpile
What should be clearly obvious, then, is that the sandpile starts level
and rapidly forms a peak, which drifts about the cell at very slow time
scales (~75 minutes!).
|
Duke Physics |
CNCS |
|---|