LANS Informal Seminar: Mark Paul

Seminar Title: The stochastic dynamics of micro and nanoscale elastic objects in fluid
Speaker: Mark Paul , Associate Professor, Dept. Of Mechanical Engineering, Virginia Tech

Date/Time: 2010-10-26 15:00
Location: Bldg 240 Conference Center 1404-1405

Description:
The dynamics of micro and nanoscale objects in fluid are stochastic and correlated due to inherent Brownian fluctuations and the long-range motion of the surrounding fluid. This has been exploited in a number of technologies including atomic force microscopy, microrheometry, and in the development of biosensors. In this talk a thermodynamic approach using the fluctuation-dissipation theorem is discussed. It is shown that the stochastic dynamics of elastic objects in fluid can be quantified from straightforward deterministic calculations that can be done on a single workstation. Using this approach, the stochastic dynamics of micro and nanoscale cantilevers are quantified for experimentally relevant conditions including cantilever arrays, complex geometries, and finite sized domains. Absolute predictions of the auto and cross-correlations of the equilibrium fluctuations in cantilever displacement are used to yield limits on the force and time sensitivity of fluctuation based
detection methods. The cross-correlations in cantilever displacement reveal interesting dynamics resulting from the interplay between the viscous and potential fluid dynamics around an oscillating object at low Reynolds number.