Accession Number : AD0733741

Title :   Experimental Determination of the Average Skin Friction Losses Associated with Several Acoustical Materials,

Corporate Author : BOEING CO RENTON WASH COMMERCIAL AIRPLANE GROUP

Personal Author(s) : Smith,R. E. ; Mauren,R. J.

Report Date : 25 NOV 1968

Pagination or Media Count : 47

Abstract : A flightworthy nacelle is being designed to reduce engine noise. This is being accomplished by installing noise attenuating material in the inlet and fan discharge duct. The noise attenuating material is of the sandwich type construction, consisting of a porous layer, a honeycomb core and an impervious skin backing. The porous layer is built up of woven fiberglass laminates impregnated with polyimide binder. This construction method allows for a variation in the roughness, porosity, cell size, core depth and core slant. It was believed that all of these variables could affect the skin friction of the acoustic material and thus affect the inlet and duct performance. Aerodynamic tests were run to compare the measured skin friction of various samples of the material to that of a smooth flat plate. (Author)

Descriptors :   (*SKIN FRICTION, *ACOUSTIC INSULATION), (*AIRCRAFT ENGINES, *ENGINE NACELLES), ENGINE NOISE, REDUCTION, DUCT INLETS, SANDWICH CONSTRUCTION, LAMINATED PLASTICS

Subject Categories : Fluid Mechanics
      Jet and Gas Turbine Engines

Distribution Statement : APPROVED FOR PUBLIC RELEASE