
Accession Number : AD0700773
Title : THEORY OF AIRFOIL RESPONSE IN A GUSTY ATMOSPHERE. PART I  AERODYNAMIC TRANSFER FUNCTION,
Corporate Author : TORONTO UNIV (ONTARIO) INST FOR AEROSPACE STUDIES
Personal Author(s) : Filotas,L. T.
Report Date : OCT 1969
Pagination or Media Count : 41
Abstract : An approximate closed form expression is derived for the loading on a twodimensional airfoil passing through an inclined sinusoidal gust. This expression is the basic transfer function required for the construction of the response to any arbitrary localized gust or continuous turbulence by Fourier superposition. The expression, based on linearized impressible lifting surface theory, is asympototically exact in the limiting cases where the reduced frequency (which is proportional to the ratio of airfoil chord to gust wavelength) is either very large. When the gust inclination is such that the nodal lines are perpendicular to the flight path, the resulting special case is a wellknown problem of unsteady airfoil theory (Sears' problem). The loading obtained for this case has the form predicted by classical theory. The value for the lift, while not exactly identical to the Sears function, differs from it only slightly in the range of reduced frequency of order unity. It is demonstrated that the accuracy for the general case is of the same order. (Author)
Descriptors : (*AIRFOILS, *GUST LOADS), TRANSFER FUNCTIONS, GUSTS, RESPONSE, TURBULENCE, ANGLE OF ATTACK, THEORY, AERODYNAMIC CHARACTERISTICS, WINGS, DOWNWASH, CANADA
Subject Categories : Aerodynamics
Aircraft
Fluid Mechanics
Distribution Statement : APPROVED FOR PUBLIC RELEASE