The Unified Finite State Airloads theory (Unified Theory) developed by Dr. Dave Peters and his former students was used to produce curves for moment and drag in an unsteady free stream. Previous work has been done to show that the Unified theory exactly matches Issacs for lift and CL in an unsteady free stream with a time varying angle of attack (α). This report will demonstrate in detail how to calculate lift, drag, moment about mid chord, and moment about quarter cord and their coefficients (CL, Cd, Cm, Cm(3/4)) using the Unified theory. A useful approximation to the Unified Theory, the Greenberg Approximation, neglects the effect of the time varying free stream velocity on the wake. The accuracy of the Greenberg approximation is quantified over the 3 cases of angle of attack for each of the calculated loads.
Mechanical Engineering and Material Sciences Independent Study
Date of Submission
Hurley, William, "Calculating Drag and Moments in an Unsteady Free Stream Using Unified Airloads Theory" (2021). Mechanical Engineering and Materials Science Independent Study. 137.