Numerical simulation of an elastic capusle under oscillating optical forces

Basazinew D. Wakjira, Islem Long, and Charles Eggleton, Department of Mechanical Engineering, UMBC

A numerical approach to simulation an elastic capsule subjected to oscillationg optical forces is presented. Our motivation stems from the desire to sort cells at high throughput. Our set up consists of an immersed elastic capsule (immersed in a Newtonian incompressible fluid), subjected to oscillating optical forces.We use the Dynamic Ray Tracing (DRT)to calcuate the optical forces that deform the cell’s membrane and we account for the restoring ealstic forces through the use of Finite Element Method(FEM). We characterize the elastic capsule response through rheological analysis.After simulations involving a wide range of frequencies, we obtain, through the use of the Fast Fourier Transform, the phase difference between the input and the reponse. We use the phase difference to compute the loss and storage moduli G’ and G” accordingly.