Akademik Veri Yönetim Sistemi
12th Computational Fluid Dynamics Conference, 1995, California, Amerika Birleşik Devletleri, 19 - 22 Haziran 1995, ss.527-539
© 1995 by Özyörük and Long. Published by the American Institute of Aeronautics and Astronautics, Inc.As transport aircraft engines get larger and larger, the dominant noise source component becomes the fan (forward and aft). A computational massively parallel aeroacoustics algorithm that has been developed to predict forward noise radiation from such engines is described in this paper. The numerical algorithm is a 4th order accurate (both in space and time), Euler/Navier-Stokes solver that is written in essentially High Performance Fortran (HPF). The scheme uses the classical four-stage Runge-Kutta time integration, central differencing for spatial derivatives, and a blend of second and sixth order, Jameson type artificial dissipation to sup press high frequency numerical oscillations. On the outer boundaries of the computational domain, non-reflecting boundary conditions are used. Specifically the algorithm has been optimized for the CM-5 of Thinking Machines Corporation. An overlap ping mixture of the fluxes of the interior points and the far-field boundary points is established by making use of the MERGE statement which the programming languages, CM Fortran and Fortran 90, facilitate. This procedure leads to a simultaneous discretization of the spatial derivatives for the three different sets of governing equations across the domain: Navier-Stokes/Euler equations, radiation boundary conditions and outflow boundary conditions. Hence, approximately 60% reduction in computing the residuals of the governing equations is obtained on the Connection Machine computers. Results for a steady engine inlet flow, oscillating flat plate in a viscous fluid, scattering from a sphere, sound radiation from a baffled oscillating piston, and sound propagation through an axisymmetric inlet are presented.