The Open and Blocked Distributed Air Transmission Lines by the Fast Fourier Transform Method

Abstract

This paper deals with the digital computer simulation of a distributed air transmission line subjected to an impulse, step, or arbitrary excitation. The rationale is based on the inverse Fourier transform principle: R(t) = F−1{G(jω) • P1(jω) } where R(t) is the response, G(jω), the system frequency function, and P1 (jω), the frequency spectrum of the input function. For input flow prediction, G(jω) is the input admittance. G(jω) represents the transfer function for pressure calculation. The predicted dynamics of a blocked and an open line subjected to arbitrary periodic excitation are compared with experimental measurements. The paper also presents the mathematical proofs to illustrate the functional behaviors of G(jω) as ω is varied from −∞ to −∞.