(571ah) Spatial and Temporal Resolution of Shear In Orbiting Dishes

It is well documented that physiological and morphological properties of anchored cells in culture are influenced by fluid shear stress. Common orbital shakers are prevalent throughout the cell culture industry because of their simplicity and they provide a means for simultaneously running tens to hundreds of tests by loading the shaker with several dishes. However, the complex flow in orbiting dishes is amenable to analytical solution for resolving shear created by the fluid motion only for simplified conditions. The only existing quantification of shear in this flow is an equation that estimates a constant scalar value of shear for the entire surface of the dish. In practice, wall shear stress values will be oscillatory rather than steady due to the traveling waveform and will vary across the surface of the dish at any instant in time. A computational model is presented here that provides complete spatial and temporal resolution of wall shear stress over the bottom surface of a dish throughout the orbital cycle. The model is reasonably well validated by reported experimental WSS values obtained using optical velocimetry at discreet locations on the bottom of an orbiting dish and by comparison with an analytical solution. The model significantly enhances the usefulness of simple shaker apparatuses in the study of hemodynamic effects on endothelial and other anchored cell cultures by providing WSS as a function of time over all dish locations.