An exact solution of the Navier-Stokes equations is obtained for the Bow between two eccentric disks rotating with the same angular velocity and one of them executing non-torsional oscillations. An analytical solution describing the Bow at large and small times after the start is given. The solutions depend on the ratio of the frequency of oscillation to the angular velocity of the disks and the ratio of the amplitude of oscillation to the angular velocity of the disks and to the distance between the axes of rotation, and the Reynolds number based on the distance between the disks and the angular velocity of the disks. The solutions for three cases when the angular velocity is greats than the frequency of oscillation or it is smaller than the frequency or it is equal to the frequency are discussed. (C) 1999 Elsevier Science Ltd. All rights reserved.