The importance of experimental airframe noise research

Numerical methods progress rapidly in terms of capabilities and efficiency. Accordingly, one could conclude that experimental activities will sooner or later disappear. In this context the paper will exemplify the use of numerical methods for the proper design and conduct of wind tunnel experiments. Examples will cover the research topics on high lift system's aero-acoustic and landing gear noise. Finally, the paper will describe the development of selected noise reduction concepts from their first experimental assessment in wind tunnels up to being flight tested.