Attenuation of Oscillatory Pressures in Instrument Lines

Abstract

A theoretical investigation has been made of the attenuation and lag of an oscillatory pressure variation applied to one end of a tube, when the other end is connected to a pressure-sensitive element. An elementary theory based upon incompressible viscous fluid is first developed. The elementary solution is then modified to take into account compressibility; finite-pressure amplitudes; appreciable fluid acceleration; and finite length of tubing (end effects). Account is taken of heat transfer into the tube. The complete theory is derived in an appendix. The results are summarized in eight graphs in a form convenient for use in computing the lag and attenuation of a sinusoidal oscillation in a transmission tube.