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The wall pressure fluctuations beneath a turbulent boundary layer with zero and non-zero pressure gradients were measured at a flat plate configuration in the Acoustic Windtunnel Braunschweig. The fluctuating pressure was measured by an array of subminiature pressure transducers. In addition, the mean flow velocity profiles within the turbulent boundary layer were obtained using hot wires. Adverse and favorable pressure gradients were realized by placing a rotatable NACA 0012 airfoil with a chord length of 40 cm above the flat plate. The one-point spectra and the two-point correlation properties are analysed. An empirical spectral model for the wall pressure fluctuations beneath an adverse pressure gradient boundary layer is developed based on the measured data. The effects of the pressure gradients on the characteristics of the wall pressure fluctuations are discussed.

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in Atlanta, Georgia, USA. The objective of this workshop was to assess the present computational capability in the area of physics-based prediction of different types of airframe noise problems and to advance the state-of-the-art via a combined effort. This documentation summarizes the results from workshop category 1 (BANC-III-1) which focuses on the prediction of broadband turbulent boundary-layer trailing-edge noise and related source quantities. Since the forerunner BANC-II workshop identified some room for improvements in the achieved prediction quality, BANC-III-1 relies on the same test cases, namely 2D NACA 0012 and DU96-W-180 airfoil sections in a uniform flow.Compared to BANC-II particularly the scatter among predictions for the DU96-W-180 test case could be significantly reduced. However, proposed adaptations of previously applied computational methods did not systematically improve the prediction quality for all requested parameters. The category 1 workshop problem remains a challenging simulation task due to its high requirements on resolving and modeling of turbulent boundary-layer source quantities.Downloaded by PURDUE UNIVERSITY on July 26, 2015 | http://arc.aiaa.org |

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