An extensive acoustic wind tunnel test campaign was conducted between March and September 2003 in the frame of the European research project ROSAS to assess experimentally the noise shielding effectiveness of classic airframe components for unconventional aircraft configurations for the first time ever in Europe. A complete aircraft model (1/11th-scale) was installed in the ONERA CEPrA19 anechoic wind tunnel, successively with a fan and a jet noise simulator representing the noise sources of an advanced, high bypass ratio turbofan. Various positions of the engine with respect to the airframe were tested with noise measurements being performed in the far field. The ROSAS test campaign has allowed gathering a comprehensive database on noise installation effects for novel aircraft concepts, yet with the shortcomings of the first of its kind. Hence the effects of the noise source characteristics, of a number of geometrical parameters and of the external flow were analyzed to some extent. Significant noise attenuation was evidenced as expected, and other secondary installation effects were also studied. This paper presents the ROSAS experiment, results and preliminary analyses of the acoustic shielding phenomena.
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