Numerical simulation of the flow field around the stratospheric observatory for infrared astronomy

Abstract

Results of steady and unsteady RANS computations of the flow around the Stratospheric Observatory for Infrared Astronomy SOFIA are presented. The observatory consists of a Boeing 747 SP with an open port in the fuselage to house a 2.5 m infrared telescope for astronomic remote sensing purposes. Results of CFD-simulations, carried out at the University of Stuttgart, show that URANS is able to capture the main effects of the unsteady cavity flow and acoustics inside the SOFIA telescope port. Pressure spectra taken at several points on the telescope's surface point out the presence of unsteady pressure fluctuations at discrete frequencies. Results compare well with experimental data, generated by NASA in wind tunnel investigations with a 7% model of the SOFIA aircraft. © 2007 Springer-Verlag Berlin Heidelberg.