A Consistency Test of Thickness and Loading Noise Codes Using Ffowcs Williams and Hawkings Equation

Abstract

The thickness noise predicted by the Ffowcs Williams and Hawkings (FW&H) equation depends on the normal velocity v n which is very sensitive to the meshing size. Isom showed that in far field a monopolar source is equivalent to a dipolar source induced by a uniform distribution of the load on the entire moving surface. The main objective of this paper is to determine a specific expression of Isom′s thickness noise in time and frequency domains for subsonic fans. The scope of the proposed expression of Isom′s thickness noise is to define a benchmark test of consistency for thickness and loading noise codes in both time and frequency domains for subsonic fans when using the free field solution of FW&H′s equation.