Future Propulsion Systems and Energy Sources in Sustainable Aviation

2Aircraft Aerodynamics – A Review

2.1 Introduction

The purpose of this chapter is to review the principles of compressible flows as they apply to aircraft and cover the traditional areas of undergraduate education in aerodynamics. It is intended to serve as a companion chapter to the main topics in the book on future propulsion systems and energy sources for sustainable aviation. By necessity, detailed step‐by‐step mathematical derivations are mostly avoided, with an emphasis placed on physics of fluids.

Aerodynamic forces and moments on an airplane stem from shear and pressure distribution on the body that integrate into a resultant force and moment. The resultant aerodynamic force has a component in the flight direction, known as drag. It also has a component normal to the flight direction, known as lift. The aerodynamic drag is a retarding force that acts on the vehicle, which needs to be overcome, or balanced by engine(s) thrust. In level steady flight, which is unaccelerated, thrust and drag are equal in magnitude. Since the dawn of flight, aircraft drag reduction has occupied a special place on aerodynamics research landscape that always involves deeper understanding of the underlying flow physics and system design optimization. Interestingly, lift also contributes to aircraft drag, known as the induced drag. In this chapter, we review briefly the underlying principles of aircraft aerodynamics, with emphasis on drag, but without lengthy derivations and proofs of the ...