Accession Number : ADP004165

Title :   Can the Singularity Be Removed in Time-Dependent Flows?

Corporate Author : MCDONNELL DOUGLAS CORP LONG BEACH CA DOUGLAS AIRCRAFT DIV

Personal Author(s) : Cebeci,T. ; Khattab,A. A. ; Schimke,S. M.

Report Date : 1984

Pagination or Media Count : 9

Abstract : The evolution of unsteady boundary layers on oscillating airfoils is studied. The computational difficulties associated with the movement of the stagnation point as a function of space and time are solved by using a novel numerical scheme. Calculations are performed for pressure distributions typical of those found near the leading edge of airfoils. Results are presented for two cases. In the first, solutions are obtained for a flow with separation and with prescribed pressure distribution; they infer that a singularity develops and is of the same type as that observed on a circular cylinder started impulsively from rest. In the second, results are obtained for the same flow and the viscous flow solutions are interacted with the external flow by using an inverse boundary-layer method. The interaction seems to remove the singularity, however, these results are preliminary and need to be checked and improved upon. (Author)

Descriptors :   *Boundary layer flow, Unsteady flow, Time dependence, Airfoils, Oscillation, Laminar flow, Pressure distribution, Numerical methods and procedures, Inversion, Stagnation point, Flow separation, Viscous flow

Distribution Statement : APPROVED FOR PUBLIC RELEASE