Abstract
We report results of an experimental protocol for determining effective diffusion coefficients in suspension flows in thin channels. The method is based on the first-passage method (FPM), a well-known aspect of probability theory. Images of identifiable individual particles are collected at a regular rate by a video camera. The times needed for individual particles to move selected distances on either side of the original position are measured. Such events are individually the 'first passage' for the selected net distances. Repeated evaluation of this statistic for the same initial conditions is done so that the history of axial motion can be summarized in a statistical manner. All images are collected in a moving frame of reference in order to limit more precisely the initial time and to make observations in a specified region of the flow. The protocol has been used in rectangular channels approximately 50 micrometers high and 500 micrometers wide to collect observations that were located approximately 12 microns in the narrow direction down from the upper surface. The local shear rate is estimated to be 100 inverse seconds. A dilute suspension of beads and a 25% suspension (volume/volume) of erythrocytes was used. Values that were measured compared well with those predicted by the Stokes-Einstein equation and with published data for blood flows.
Original language | English |
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Title of host publication | American Society of Mechanical Engineers, Bioengineering Division (Publication) BED |
Pages | 57-58 |
Number of pages | 2 |
Volume | 43 |
State | Published - 1999 |
Event | Advances in Bioengineering - 1999 (The ASME International Mechanical Engineering Congress and Exposition) - Nashville, TN, USA Duration: Nov 14 1999 → Nov 19 1999 |
Conference
Conference | Advances in Bioengineering - 1999 (The ASME International Mechanical Engineering Congress and Exposition) |
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City | Nashville, TN, USA |
Period | 11/14/99 → 11/19/99 |
ASJC Scopus subject areas
- General Engineering