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Taking Advantage of Reduced Droplet-surface Interaction to Optimize Transport of Bioanalytes in Digital Microfluidics
Published on: November 10, 2014
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Optimal transport and control of active drops
Suraj Shankar1, Vidya Raju2, L Mahadevan1,2,3
1Department of Physics, Harvard University, Cambridge, MA 02138.
Summary
Researchers used optimal control theory to guide active fluid drops, discovering a "gather-move-spread" strategy for efficient transport. This method minimizes viscous dissipation and enhances control over active matter dynamics.
Area of Science:
- Active matter physics
- Fluid dynamics
- Optimal control theory
Background:
- Active systems exhibit complex space-time patterns.
- Controlling active matter is a key inverse problem.
Purpose of the Study:
- To control the transport of active fluid drops using optimal control theory.
- To determine active stress profiles for minimal viscous dissipation during drop transport.
Main Methods:
- Parametrization of drop position and size using lubrication theory.
- Application of optimal control theory to active fluid dynamics.
- Analysis of continuum models with surface tension and active controls.
Main Results:
- Identified a "gather-move-spread" strategy for optimal drop displacement.
- Established an optimal bound for drop displacement relative to its size.
- Observed complex behaviors like futile oscillations and varied drop morphologies due to competing forces.
Conclusions:
- Optimal control provides a tractable framework for active matter manipulation.
- The study paves the way for spatiotemporal control of active matter.
- Balancing dissipation and transport cost is crucial for optimal strategies.
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