Far Field Numerical Boundary Conditions for Internal and Cascade Flow Computations
Abstract
The present report extends the approach developed by A. Verhoff for the treatment of the far field boundary conditions, Verhoff and O'Neil (1984), to more general formulations of the Euler equations and to cascade geometries. Linearized solutions of the Euler equations are developed for the perturbations from the uniform free stream, for ducts and cascades. These solutions are based on the conditions that the waves associated with incoming characteristics should decay to zero in the far field, while the variables associated to the outgoing characteristics are derived from the numerical internal solution. The exact linearized solutions are based on a Fourier expansion in the direction along the inlet or exit boundaries. Results, obtained from an Euler code are shown for ducts and cascades, comparing calculations for exit boundaries at increasingly closer distance to the central flow region. The method is also valid for nonisentropic flows. The results show that the corrections to the uniform boundary conditions derived from the analysis allow a considerable reduction of the computational domain, with the corresponding savings in computational times. (KR)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1988
- Accession Number
- ADA216703
Entities
People
- Charles Hirsch