Chaos and threshold for irreversibility in sheared suspensions Export

@article{citeulike:438091, abstract = {Systems governed by time reversible equations of motion often give rise to irreversible behaviour1, 2, 3. The transition from reversible to irreversible behaviour is fundamental to statistical physics, but has not been observed experimentally in many-body systems. The flow of a newtonian fluid at low Reynolds number can be reversible: for example, if the fluid between concentric cylinders is sheared by boundary motion that is subsequently reversed, then all fluid elements return to their starting positions4. Similarly, slowly sheared suspensions of solid particles, which occur widely in nature and science5, are governed by time reversible equations of motion. Here we report an experiment showing precisely how time reversibility6 fails for slowly sheared suspensions. We find that there is a concentration dependent threshold for the deformation or strain beyond which particles do not return to their starting configurations after one or more cycles. Instead, their displacements follow the statistics of an anisotropic random walk7. By comparing the experimental results with numerical simulations, we demonstrate that the threshold strain is associated with a pronounced growth in the Lyapunov exponent (a measure of the strength of chaotic particle interactions). The comparison illuminates the connections between chaos, reversibility and predictability.}, author = {Pine, D. J. and Gollub, J. P. and Brady, J. F. and Leshansky, A. M.}, citeulike-article-id = {438091}, citeulike-linkout-0 = {http://dx.doi.org/10.1038/nature04380}, citeulike-linkout-1 = {http://dx.doi.org/10.1038/nature04380}, day = {15}, doi = {10.1038/nature04380}, issn = {0028-0836}, journal = {Nature}, keywords = {chaos, colloids, journal-club, reversibility, reynolds\_number, threshold}, month = {December}, number = {7070}, pages = {997--1000}, posted-at = {2009-10-07 17:21:31}, priority = {0}, publisher = {Nature Publishing Group}, title = {Chaos and threshold for irreversibility in sheared suspensions}, url = {http://dx.doi.org/10.1038/nature04380}, volume = {438}, year = {2005} }

TY - JOUR ID - citeulike:438091 L3 - citeulike-article-id:438091 N2 - Systems governed by time reversible equations of motion often give rise to irreversible behaviour1, 2, 3. The transition from reversible to irreversible behaviour is fundamental to statistical physics, but has not been observed experimentally in many-body systems. The flow of a newtonian fluid at low Reynolds number can be reversible: for example, if the fluid between concentric cylinders is sheared by boundary motion that is subsequently reversed, then all fluid elements return to their starting positions4. Similarly, slowly sheared suspensions of solid particles, which occur widely in nature and science5, are governed by time reversible equations of motion. Here we report an experiment showing precisely how time reversibility6 fails for slowly sheared suspensions. We find that there is a concentration dependent threshold for the deformation or strain beyond which particles do not return to their starting configurations after one or more cycles. Instead, their displacements follow the statistics of an anisotropic random walk7. By comparing the experimental results with numerical simulations, we demonstrate that the threshold strain is associated with a pronounced growth in the Lyapunov exponent (a measure of the strength of chaotic particle interactions). The comparison illuminates the connections between chaos, reversibility and predictability. IS - 7070 JF - Nature SN - 0028-0836 EP - 1000 TI - Chaos and threshold for irreversibility in sheared suspensions PB - Nature Publishing Group VL - 438 SP - 997 KW - chaos KW - colloids KW - journal-club KW - reversibility KW - reynolds_number KW - threshold AU - Pine, DJ AU - Gollub, JP AU - Brady, JF AU - Leshansky, AM PY - 2005/12/15/ UR - http://dx.doi.org/10.1038/nature04380 ER -