Fluid Inertia Forces in Squeeze Film Dampers

Abstract Fluid inertia forces in Squeeze Film Dampers (SFDs) are obtained for short and long dampers using an energy approximation based on the assumption that the velocity profiles with inertia are the same as those for an inertialess fluid. It is shown that the inertia forces thus obtained are proportional to the usual radial, centripetal, tangential and Coriolis accelerations of the journal, plus an additional nonlinear acceleration. The inertia coefficients of the dampers are obtained, for both uncavitated and cavitated dampers, and are plotted versus the eccentricity ratio for centered, nearly circular whirl. The inertia forces obtained by the energy approximation are compared to an exact linearized solution for centered, circular whirl, and good agreement is found for both short and long dampers in the Reynolds number range of ordinary SFD application.