METHOD AND APPARATUS FOR CONTROLLING TONAL NOISE FROM SUBSONIC FANS

摘要

A method and apparatus for reducing a selected tonal noise generated by a fan operating in a non-uniform flow by locating at least one obstruction in the non-uniform flow such that the at least one obstruction generates a noise that is out of phase with the selected tonal noise. The noise generated by the at least one obstruction interferes with the selected tonal noise, thus reducing the selected tonal noise. It is also contemplated to use additional obstructions to reduce other tonal noises generated by the fan.