Installation Effects of a Propeller Mounted on a Wing with Coanda Flap. Part Ⅱ: Numerical Investigation and Experimental Validation

摘要

Within the framework of the German project "Biirgernahes Flugzeug" (Citizen Friendly Aircraft), we are investigating the effect of installation on propeller sound. A nine-bladed propeller installed in front of a wing equipped with a Coanda flap is considered. This configuration produces significant high lift and thereby considerably influences the inflow condition of the propeller. The sound generated by the propeller is furthermore shielded by and reflected off the wing. In this contribution, we present an implementation of an acoustic propeller model in a finite differences CAA (computational aeroacoustics) code. Comparisons of isolated propeller computations in a quiescent flow with an analytical model illustrate the correct numerical implementation. The verification of the implementation is presented for an example of an isolated propeller. A comparison for the installed propeller with experiments is conducted for different settings.