Prairie Air is drawn from the bleed air header, sent through a cooler then through the propulsion shafting to the propeller hubs where it is emitted from small holes on the propeller blades. This fills the vacuum left by the rotating blades as the water "boils," allowing cavitation bubbles to contract more slowly as area of underpressure is minimized. The Prairie Air System supplies air along the propeller blade leading edge to reduce the hydrodynamic noise originating at the propeller. MACHALT Proposals Under Development will replace Prairie/Masker air system portable flow meters with an electronic airflow monitoring system. Improper Prairie/Masker airflow rates are an ASW mission degrade. During ASW operations, there is no instantaneous way of determining if the airflow rates are accurate at any given time. Gas turbine ships routinely operate systems inport and at sea, to avoid marine growth from plugging holes in blade tips and masker belts. Prairie-Masker is used during both active and passive undersea warfare operations. Very little sound will penetrate a curtain of air bubbles, making them very efficient as masking for noise sources. The large difference in characteristic impedance (c) between the air bubbles and the surrounding water make them very efficient as reflectors of acoustic energy. The Prairie system is fitted to the ship's propellers, while Masker is fitted to the external hull in the vicinity of the propulsion plant.Īir bubbles can be employed to mask potential targets or to provide alternate targets. A noise reduction system called "Prairie Masker" was developed by the US Navy for several classes of its warships (including the Spruance, Perry, Arleigh Burke, and Ticonderoga) to reduce or mask their self-noise.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |