Light-scattering properties of undiluted human blood subjected to simple shear

An experimental investigation was performed into the effect of simple shear on the light-scattering properties of undiluted human blood. Undiluted human blood was enclosed between two glass plates with an adjustable separation between 30 and 120 microns and with one plate moving parallel to the other. For various shear rates and layer thicknesses, the angular light distribution and the collimated transmission were measured for 633-nm light. For shear rates above 150 s-1, the transmission results directly yielded a total attenuation coefficient of 120 mm-1. At lower shear rates the total attenuation followed an irregular pattern. From the angular intensity distributions, the anisotropy for single scattering was deduced by inverse Monte Carlo simulations. A continuous increase of the average cosine g with the shear rate was observed, with g in the range 0.95-0.975.