number of different type of flow chambers have been designed to study adhesion between cells in vitro. One important design feature is the ability to have a wide range of shear stresses. This ability allows a wide range of data to be collected in a single experiment, reducing experimental variability. One such device is a radial flow channel. In this device the fluid flows from a source in the radial direction. The total flow rate is Q, the viscosity of the fluid is mu, and the spacing between the plates is h. Determine the wall stress sigma rz as a function of r. Assume laminar, newtonian flow.