ERROR ANALYSIS FOR THE 2-LOAD METHOD USED TO MEASURE THE SOURCE CHARACTERISTICS OF FLUID MACHINES

A number of papers have been published on characterization of fluid machines as sources of fluid borne noise, using the acoustic two-pole analogy. In this analogy it is assumed that the source can be described as a linear time invariant acoustic system characterized by a source pressure ps (Thevenin equivalent) or a source volume flow Qs (Norton equivalent) and an internal source impedance Zs. The different measurement methods used to determine these quantities are the standing wave tube method, the two-microphone method, the two-load method, and the similar three- and four-load methods. For the two-load method an error analysis is presented.