Patent ID: 8286654

Claim:
A gas turbine engine comprising: a nacelle enclosing a fan section, a compressor, a combustor and a turbine, said nacelle including an inner nacelle surface defining an inlet duct having a flow area; and an actuator disposed in said inner nacelle surface for selectively reducing said flow area to increase the Mach number of air into said gas turbine engine to enhance acoustic attenuation associated with said inlet duct, wherein said actuator comprises an inflatable bladder disposed in said nacelle and having an inflated state wherein said inflatable bladder protrudes into said flow area of said inlet duct, and, in said inflated state, a portion of said inflatable bladder disposed in an upper portion of said inlet duct has a smaller protrusion into said flow area relative to a portion of said inflatable bladder disposed at a lower portion of said inlet duct.