Dynamics of nonspherical capsules in shear flow
Prosenjit Bagchi1, R Murthy Kalluri
1Department of Mechanical & Aerospace Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA. pbagchi@jove.rutgers.edu
Summary
Numerical simulations reveal three distinct dynamics for oblate capsules in shear flow: swinging, vacillating-breathing, and tumbling. Capsule deformation and orientation coupling strongly influences motion transitions.
Area of Science:
- Fluid Dynamics
- Computational Science
Background:
- Understanding capsule behavior in shear flow is crucial for biological and industrial applications.
- Previous models often simplify the complex interplay between capsule deformation and orientation.
Purpose of the Study:
- To investigate the dynamics of oblate capsules in linear shear flow using 3D numerical simulations.
- To analyze the coupling between shape deformation and orientation across various viscosity contrasts, shear rates, and aspect ratios.
Main Methods:
- Three-dimensional numerical simulations employing a front-tracking method.
- Exploration of a wide parameter space including viscosity contrast, capillary number, and aspect ratio.
Main Results:
- Identification of three low-capillary number motion modes: swinging (OS), vacillating-breathing (VB), and tumbling (TU).
- Observation of transient motions and mode transitions at higher capillary numbers.
- Strong coupling between shape deformation and orientation, peaking in the VB mode.
Conclusions:
- Capsule dynamics in shear flow are highly dependent on viscosity contrast and shear rate.
- The coupling between deformation and orientation significantly impacts motion transitions, with notable deviations from existing theories.
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