- Impingement cooling was studied on smooth target walls in rotating two-pass rectangular channels with a sharp 180-deg turn. Jets impinged opposite to the direction of rotation in one channel, and in the same direction of rotation in the other channel. Spent air moved in the radially outward direction in the first impingement channel and radially inward in the second impingement channel. Jet Reynolds numbers and rotation numbers varied from 4 103 to 1 104 and 0 to 0.0133, respectively. Rotation changed the pressure level and distribution, but did not significantly alter the jet velocity distribution in the two-pass impingement channel. However, rotation-induced Coriolis and centrifugal forces decreased the Nusselt number values 20 and 25% in the impingement channels and turn region, respectively. Nusselt number values in the turn region were 60% higher when compared with those in the impingement channels for higher jet-flow rates and over the range of rotation speeds tested. Copyright 1998 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.