Status of Unsteady Aerodynamic Prediction for Flutter of High-Performance Aircraft

Abstract

Current production unsteady aerodynamics codes are based on panel methods. The capabilities present in these methods to model complex shapes represents one of the major advancements in this methodology. A second advancement is that the new codes are now formulated based on a unie ed analytical capability throughout the Mach range. Examples of these capabilities will be demonstrated. Finally, based on the discussion of requirements for e utter analyses of high-performance aircraft, a description of the needs for the future is presented.Itishoped thatthese recommendations willprovide guidance to those investigators working in the e eldof unsteady aerodynamics. II. Background A. Unsteady Aerodynamic Methods Strip theory aerodynamics originated in the early 1940s, 1;2 and this method was the primary aerodynamic tool for e utter analyses for many years.In 1966, Yates 3 proposed modifying CL® toaccount for e nite span effects with the result being referred to as modie ed strip theory. This aerodynamic method, coupled with the normal modeapproach,and the V‐g‐! solution technique formedthe basis for production e utter analyses in the late 1960s, and it was to this methodology that the author was e rst exposed to production e utter analyses.