The Heat Transfer Engineering Cover Page, shown to the right, shows the temperature distribution of a rotating disk obtained from a transient three-dimensional simulation of a computer hard drive performed by Manoj Kumar Nagalla at Southern Illinois Univeristy Edwardsville. The hard drive had two disks and four arms, and rotated at 12,000 rpm. The ambient and spindle temperatures were 300 and 310 K. Viscous heating of air was included in the model. The turbulence inside the drive was handled by Reynolds Stress Model. The isotherms show a strong temperature variation for the conditions used in this simulation. The arm seen on the right side of the picture has clearly caused a non-uniform and asymmetric temperature field throughout the disk. The figures are available in pdf format below.