Computational chain for virtual fly-over simulations applied to fan noise

Abstract

To ensure an aircraft’s compliance with noise regulations, expensive fly-over tests are required. Up until now, there is no numerical alternative to the experimental Standard procedure. In this paper, a step is taken toward enabling a ”virtual fly-over” in the future. The authors restricted themselves to the study of tonal fan noise from ist generation in the fan stage to its propagation to observer positions at ground level. As one large simulation tackling the entire problem at full-scale Reynolds numbers would have been computationally too demanding, a computational chain is established. This computational chain splits the large task into smaller subtasks linked by interfaces. Each of these subtasks can then be solved by a suitable calculation technique. For the presented case, the subtasks include the mean flow computation, the noise generation, and the noise propagation. The computational chain - including the involved tools and interfaces - is discussed in detail and first results are presented for isolated and installed engine configurations.