Granular Realization of the Smoluchowski-Feynman Ratchet

Granular Realization of the Smoluchowski-Feynman Ratchet

Physics of Fluids group - University of Twente

Video clip (2.1 MB; real-time, 25 frames per second) from the result of a freshman's physics project showing an exact copy of Smoluchowski's device in a granular gas. Clearly Smoluchowski's Gedankenexperiment works in a granular gas, but analyzability asks for a more clever design of the experimental setup.

Video animation (9.9 MB; in slow motion, 40 times slower than real-time) of a MD simulation of the symmetric system: The driving parameters are chosen such that the symmetry in the granular gas is spontaneously broken and a convection roll is formed, reinforcing the rotation of the vanes, as discussed in the article.

Video clip (8.7 MB; real-time, 25 frames per second) of the ratchet system for 2000 particles and h = 51 mm at mild shaking (a = 3.5 mm, f = 20 Hz). The motion of the system is clearly confined to the X configuration, corresponding to the situation of Fig. 3a of the main text. Note that the coating that has been attached to the left hand-side of each vane to break the symmetry is hardly visible in the video.

Video clip (8.7 MB; real-time, 25 frames per second) of the ratchet system for 2000 particles and h = 51 mm at strong shaking (a = 3.5 mm, f = 55 Hz). From the viewpoint of the sensor, the motion of the ratchet is almost exclusively in the counter-clockwise direction (see Fig. 3c of the main text).