Results Obtained in Tests Using Three Simple Methods for Converting Frequency-Domain Aerodynamics to the Time Domain

摘要

The approach used here has been to obtain time-domain representations that are sums of exponentials. This, in turn, requires frequency domain approximations that are rational functions of the Laplace transform variables. Three simple methods for obtaining rational function approximations for frequency domain unsteady aerodynamic data have been tested. A number of satisfactory approximations were achieved, but many approximations were poor. In this report, the use of equally spaced poles proved to be the most successful. Keywords: Unsteady flow; Aerodynamics; Control theory; Active control; Least squares method; and Australia.