Benchmarking of Trailing-Edge Noise Computations - Outcome for the BANC-II Workshop

Kurzfassung

The Second Workshop on Benchmark Problems for Airframe Noise Computations, BANC-II, was held on 7-8 June 2012 in Colorado Springs, CO, USA. The objective of this workshop was to assess the present computational capability in the area of physics-based prediction of dierent types of airframe noise problems and to advance the state-of-the-art via a combined effort. This paper summarizes the results from workshop category 1 which focuses on the prediction of broadband turbulent boundary-layer trailing-edge noise and related source quantities. 2D airfoil sections, namely a NACA0012 and DU-96-180, served as test cases. Code-to-code comparisons in this category were mainly restricted to relatively fast RANS-based methods applying statistical noise theory. Overall, the prediction capability was sufficient to capture the principal trailing-edge farfield noise scaling behavior in the mid-frequency range (about 1 kHz <= fc <= 5 kHz), i. e. the measured dependence of noise on angle-of-attack or free stream velocity. Differences in predicted trends appeared at lower and higher frequencies. Moreover, a comparatively large scatter among the DU-96-180 prediction results was observable, indicating individual room for improvement in the applied approaches.