Boundary Conditions for Direct Computation of Aerodynamic Sound Generation
- Creators
- Colonius, Tim
- Lele, Sanjiva K.
- Moin, Parviz
Abstract
Accurate computation of the far-field sound along with the near-field source terms associated with a free shear flow requires that the Navier-Stokes equations be solved using accurate numerical differentiation and time-marching schemes, with nonreflecting boundary conditions. Nonreflecting boundary conditions have been developed for two-dimensional linearized Euler equations by Giles. These conditions are modified for use with nonlinear Navier-Stokes computations of open flow problems. At an outflow, vortical structures are found to produce large reflections due to nonlinear effects; these reflection errors cannot be improved by increasing the accuracy of the linear boundary conditions. An exit zone just upstream of an outflow where disturbances are significantly attenuated through grid stretching and filtering is developed for use with the nonreflecting boundary conditions; reflections from vortical structures are decreased by 3 orders of magnitude. The accuracy and stability of the boundary conditions are investigated in several model flows that include sound radiation by an energy source in a uniformly sheared viscous flow, the propagation of vortices in a uniform flow, and the spatial evolution of a compressible mixing layer.
Additional Information
© 1992 by the American Institute of Aeronautics and Astronautics, Inc. Received July 2, 1992; revision received Oct. 8, 1992; accepted for publication Oct. 20, 1992; published online: May 17, 2012. This work was supported by the Office of Naval Research under Contract ONR-N00014-88-K-0592. The computer time was provided by NASA Ames Research Center.Attached Files
Published - ColoniusLeleMoin1993.pdf
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Additional details
- Eprint ID
- 97446
- Resolver ID
- CaltechAUTHORS:20190726-104728916
- Office of Naval Research (ONR)
- N00014-88-K-0592
- Created
-
2019-07-29Created from EPrint's datestamp field
- Updated
-
2021-11-16Created from EPrint's last_modified field
- Other Numbering System Name
- AIAA Paper
- Other Numbering System Identifier
- 92-2075