Fundamental Investigation of an Oil Damper 2nd Report Analysis Based on the Unsteady Flow Assumption

概要

論文の詳細を見る
This paper deals with dynamic characteristics of an oil damper, whose piston is vibrating axially in a viscous fluid filling a fixed circular cylinder. Assuming a one-dimensional flow past the annular cross-sectional clearance between the piston and the cylinder, we evaluated a drag force acting on the piston. And the analytical results were compared with experimental observations. The following results were obtained. (1) The velocity profile in the clearance depends on the dimensionless factor λ= h√<ω/(2ν)>, where h, ω, ν are radial clearance, circular frequency and kinematic viscosity, respectively. Being a parabolic distribution within λ<2 as is the case in a steady flow, for larger values of λ the velocity profile approaches uniformity over the clearance. (2) Pressere drag and friction drag exerted on the piston are both out of phase with the velocity of the piston. Therefore "damping coefficient" and "added mass" must be deemed the representative characteristics of the oil damper.
一般社団法人日本機械学会の論文