Ericksen number

In the study of liquid crystals, the Ericksen number denoted by $\mathrm{Er}$ , is a dimensionless number used to describe the deformation of the director field under flow. It is defined as the ratio of the viscous to elastic forces. In the limit of low Ericksen number the elastic forces will exceed the viscous forces and so the director field will not be strongly affected by the flow field. The Ericksen number is named after Jerald Ericksen.

References

Stark, H. & Ventzki, D. (2002), "Non-linear Stokes Drag of Spherical Particles in a Nematic Solvent", Europhysics Letters 57 (1): 60–66, doi:10.1209/epl/i2002-00541-0 .