Resumen de Aerodynamic Lift, Part 2: A Comprehensive Physical Explanation
In the companion paper, “Aerodynamic Lift, Part 1: The Science,”1 I described the key features of lifting flows. The objective of the present paper is to explain those features and the cause-and-effect relationships between them in a manner consistent with the laws of physics.
Most of the qualitative explanations of aerodynamic lift that have been put forward by others have followed either of two main approaches: Bernoulli-based explanations as given by J. D. Anderson,2 and downward-turning explanations based on Newton’s second and third laws, as advocated by Smith,3 Waltham,4 and D. Anderson and Eberhardt.5 Eastlake6 and others have argued that both approaches are basically correct and that either can be satisfactory. Weltner7,8 and Babinsky9 put forward explanations based on streamline curvature that are closely related to the simpler downward-turning explanations.
The explanation presented here is motivated by the observation that neither the Bernoulli approach by itself nor the downward-turning or streamline curvature approach by itself adequately explains all of the essential cause-and-effect relationships in a lifting flow, and that a satisfactory explanation requires elements of both and must deal in more detail with what the flow actually does. This new explanation is similar to the one given in my book,10 but with enhancements that I hope make it clearer.
