Accession Number:

ADA261925

Title:

Unsteady Airfoil Flow Solutions on Moving Zonal Grids

Descriptive Note:

Master's thesis

Corporate Author:

NAVAL POSTGRADUATE SCHOOL MONTEREY CA

Personal Author(s):

Report Date:

1992-12-17

Pagination or Media Count:

146.0

Abstract:

Investigation of subsonic and transonic steady and unsteady flowfields over airfoils is an active area of current computational and experimental research. The performance of rotary wing and fixed wing aircraft can be enhanced by taking advantage of unsteady phenomena such as dynamic lift. However, several undesirable effects have prevented designers from taking advantage of these concepts. In the past few years many advances have been made in algorithm, development for the numerical solution of the Euler and the Navier Stokes equations. In this study, these new techniques are applied to body fixed zonal grid approach. This zonal approach is more computationally efficient in solving the governing equations than previous approaches, and has certain advantages over the standard single moving grid approach. The zonal grids consists of two grids, one being the inner grid which is fixed to the airfoil, and the other being the outer grid which extends to the far field or to a specified outer boundary. The inner grid is allowed to rotate with the body, while the outer grid remains fixed. The thin-layer Navier-Stokes equations are solved for inner grid, and the Euler equations are solved for the outer grid. Communication between the two grids is accomplished by interpolated the flow quantities at the zonal interface. Solutions are obtained for flows at fixed angles of incidence, and for unsteady flows over pitching and oscillating airfoils. The computed results are in good agreement with available experimental data.

Subject Categories:

  • Aerodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE