An approximate analysis of axisymmetric stress field by using transmission light flow birefringence technique.

A method for analyzing an approximately axisymmetric stress field was established. The extinction angle obtained from the isoclinic pattern was taken to be almost equal to the inclination of the principal axis of a refractive index ellipsoid and the phase difference to be dependent only on local values of the double refractive index. Analysis of the local values of the primary double refractive index was made using an approximate equation. The method was applied to stress analysis of the flow around a sphere constituting an example of an axisymmetric flow field. The assumptions cited were shown to be reasonable and the method expressed effective for approximate stress analysis of axisymmetric flow fields with double refractive indices rising to the axis, if suitable correction for such indices is made. (P.J.B.)