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Central-difference and upwind-biased schemes for steady and unsteady Euler aerofoil computations

Published online by Cambridge University Press:  04 July 2016

C. B. Allen*
Affiliation:
Department of Aerospace Engineering, University of Bristol

Abstract

Two numerical methods are presented for the computation of steady and unsteady Euler flows. These are applied to steady and unsteady flows about the NACA 0012 aerofoil, using structured grids generated by the transfinite interpolation technique. An explicit central-difference scheme is produced based on the cell-vertex method of Ni modified by Hall. The method is second-order accurate in time and space, and with flow quantities stored at boundaries the boundary conditions are simple to apply. This is a definite advantage over the cell-centred approach of Jameson, where extrapolation of the flow quantities is required at the boundaries, making unsteady boundary conditions difficult to apply. An explicit upwind-biased scheme is also produced, based on the flux-vector splitting of van Leer. The method adopts a three stage Runge-Kutta time-stepping scheme and a high-order spatial discretisation which is formally third-order accurate for one-dimensional calculations. The upwind scheme is shown to be slightly more accurate than the central-difference scheme for steady aerofoil flows, but it is not clear which is the more accurate for unsteady aerofoil flows. However, the central-difference scheme requires less than half the CPU time of the upwind-difference scheme, and hence is attractive, especially when considering three-dimensional flows. The transfinite interpolation technique is ideal for generating moving structured grids due to its simplicity, and grid speeds are available algebraically by the same interpolation as grid points. The method is also ideal for use in a multi-block approach.

Type
Research Article
Copyright
Copyright © Royal Aeronautical Society 1995 

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References

1. Jameson, A., Schmidt, W., and Turkel, E. Numerical Solution of the Euler equations by finite volume methods using Runge-Kutta time stepping schemes, AIAA Paper 81-1259, 1981.Google Scholar
2. Kroll, N. and Jain, R.K. Solution of two-dimensional Euler equations - experience with a finite volume code, DLR report, DFVLR-FB 87-41, 1987.Google Scholar
3. Batina, J.T. Unsteady Euler airfoil solutions using unstructured dynamic meshes, AIAA Paper 89-0115, 1989.Google Scholar
4. Williams, A.L. and Fiddes, S.P. Solution of the 2-D unsteady Euler equations on a structured moving grid, Bristol University Aero. Eng. Dept. Report No. 453, 1992.Google Scholar
5. Salas, M.D. (Ed.). Accuracy of unstructured grid techniques workshop, Nasa Langley Research Center, January 1990, (Nasa conference proceedings to be published).Google Scholar
6. Ni, R.-H. A multiple grid scheme for solving the Euler equations, paper 81-1025, Proc. AIAA Fifth Computational Fluid Dynamics Conference, Palo Alto, California, 1981.Google Scholar
7. Hall, M.G. cell-vertex multigrid schemes for solution of the Euler equations. In: Numerical Methods For Fluid Dynamics II, Eds. Morton, K.W. and Baines, M.J., Oxford University Press, 1986, pp 303345.Google Scholar
8. van-leer, B. Flux-vector splitting for the Euler equations, Lecture Notes in Physics, 1982, 170, pp 507512.Google Scholar
9. Parpia, I.H. Van-Leer flux-vector splitting in moving coordinates, AIAA Journal, January 1988,26, pp 113115.Google Scholar
10. Anderson, W.K. Thomas, J.L. and van-leer, B. Comparison of finite volume flux vector splittings for the Euler equations, AIAA J, September 1986,24, pp. 14531460.Google Scholar
11. Turkel, E. and van-leer, B. Runge-Kutta methods for partial differential equations, ICASE Report, 1983.Google Scholar
12. Thomas, P.D. and Lombard, C.K. Geometric conservation law and its application to flow computations on moving grids, AIAA J, October 1979, 17, pp 10301037.Google Scholar
13. Gordon, W.J. and Hall, C.A., Construction of curvilinear coordi nate systems and applications of mesh generation, Int J Numer Meth Eng, 1973, 7, pp 461477.Google Scholar
14. Eriksson, L.E. Generation of boundary-conforming grids around wing-body configurations using transfinite interpolation, AIAA J, 1982,20,(10), pp 13131320.Google Scholar
15. Test Cases for Inviscid Flow Field Methods, Agard Agardograph AR-211, 1985.Google Scholar
16. Compendium of Unsteady Aerodynamic Measurements, AGARD-R- 702, 1982.Google Scholar
17. Allen, C.B., Fiddes, S.P., and Williams, A.L. Description and ini tial development of a coupled viscous-inviscid method for unsteady transonic flow, Bristol University Aero. Eng. Dept. Report No. 459, 1992.Google Scholar
18. Venkatakrishnan, V. Computation of Unsteady Transonic Flows Over Moving Aerofoils, PhD Dissertation, Dept. of Mechanical and Aerospace Engineering, Princeton University, 1986.Google Scholar
19. Gaitonde, A.L. A dual-time method for solution of the unsteady Euler equations, Aeronaut J, October 1994, 98, (978), pp 283291.Google Scholar