| 摘要 |
An apparatus for inducing high frequency out-of-phase, vibrations in adjacent span-wise panel portions of a plate type structure, such as an airfoil blade of a gas turbine engine. The apparatus includes a novel bifurcated duct for conducting and directing two out-of-phase streams of gaseous flow, and a uniquely structured air chopper which generates the two out-of-phase gaseous streams. The duct has an upstream end with which the output of the air chopper is in communication, and a stepped-down downstream end at which the airfoil blade (or other plate type structure specimen that is to be tested) is held, supported, and positioned in a chord-wise direction, such that the two out-of-phase gaseous streams impinge upon, and induce the same high frequency vibration in, two preselected, adjacent, span-wise panel portions of the specimen, thereby the panel portions vibrate out-of-phase.
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