Transport phenomena in zonal centrifuge rotors. I. Velocity and shear-stress distributions of fluid during acceleration.

An analysis is presented for the evaluation of velocity components and shear-stress distributions of fluid in zonal centrifuge rotors during acceleration. Analytical expressions for the distribution of tangential and radial velocity components and the tangential shear-stress and the radial shear-stress distributions of fluid are obtained for the transient case. Characteristics of each distribution for a typical density gradient liquid in a zonal centrifuge rotor are computed from the relations derived, and are presented as figures. An unusual phenomenon-the tangential velocity of the gradient exceeding the velocity of the rotor during a particular period of acceleration-is demonstrated.