Birefringence is an optical property of materials where light splits into two different rays, each traveling at a different speed and direction when passing through the material.
Phase retardation (∆) refers to the difference in the phase of light waves as they pass through a birefringent material (like a flowing fluid with aligned molecules).
∆ is Phase retardation, C₁: First-order stress-optic coefficient, σxx, σyy: Stress components in x and y directions
The second-order stress-optic law is needed to accurately predict birefringence in thin fluid flows. Shear-thinning affects birefringence, mainly due to changes in second order Stress optics coefficient c2 rather than just viscosity.
As shear rate increases, C₂ decreases and phase retardation increases. The phase retardation decreases in the radial direction and increases with increasing flow rate.
source:
https://arxiv.org/html/2503.10261v1
0 comments:
Post a Comment