
Accession Number : AD0714076
Title : A Theory of TwoDimensional Airfoils with Strong Inlet Flow on the Upper Surface.
Descriptive Note : Final rept. 1 Nov 6731 Dec 69,
Corporate Author : CALIFORNIA INST OF TECH PASADENA
Personal Author(s) : Serdengecti,Sedat ; Marble,Frank E.
Report Date : AUG 1970
Pagination or Media Count : 59
Abstract : The twodimensional theory of airfoils with arbitrarily strong inlet flow into the upper surface was examined with the aim of developing a thinairfoil theory which is valid for this condition. Such a theory has, in fact, been developed and reduces uniformly to the conventional thinwing theory when the inlet flow vanishes. The integrals associated with the arbitrary shape, corresponding to the familar Munk integrals, are somewhat more complex but not so as to make calculations difficult. To examine the limit for very high ratios of inlet to freestream velocity, the theory of the Joukowski airfoil was extended to incorporate an arbitrary inlet on the surface. Because this calculation is exact, phenomena observed in the limit cannot be attributed to the linearized calculation. These results showed that airfoil theory, in the conventional sense, breaks down at very large ratios of inlet to freestream velocity. This occurs where the strong induced field of the inlet dominates the freestream flow so overwhelmingly that the flow no longer leaves the trailing edge but flows toward it. Then the trailing edge becomes, in fact a leading edge and the Kutta condition is physically inapplicable. For the example in this work, this breakdown occurred at a ratio of inlet to freestream velocity of about 10. This phenomena suggests that for ratios in excess of the critical value, the flow separates from the trailing edge and the circulation is dominated by conditions at the edges of the inlet. (Author)
Descriptors : (*AIRFOILS, THEORY), WING INLETS, FANS, VERTICAL TAKEOFF AIRCRAFT, AERODYNAMIC CHARACTERISTICS
Subject Categories : Aerodynamics
V/STOL
Distribution Statement : APPROVED FOR PUBLIC RELEASE