ENGINEERING TRIPOS PART IIB – 2012/2013

Module 4A7 - Aerodynamics

AIMS

This course aims to develop the basic ideas necessary to enable the student to understand some advanced concepts in aerodynamics. In particular the course will cover the aerodynamic effects that constrain an aircraft design. The course will highlight those factors determining the configuration of aircraft for different duties relating them to the effect of compressibility at transonic speeds, the control of boundary layers to benefit from laminar flows and the estimation of aerodynamic loads on the aircraft structure. Coursework will illustrate basic physics, via transonic airfoil design and the integration of these basics via a study of the trade-offs made in producing a design for a given specification. The course will end by reviewing the environmental impact of aviation and show how aircraft design might change to reduce this impact.

LECTURE SYLLABUS

Introduction to transonic wings (2L, Dr. J. P. Jarrett)

• Review of 3A3 material: boundary layers and drag estimation;
• Transonic flow about two-dimensional aerofoils;
• Shock-boundary layer interaction;
• Supercritical aerofoils with delayed shock-induced drag rise.

Transonic aerofoil design (4h coursework, Dr. J. P. Jarrett)

• This coursework section will allow the interactive design of a transonic aerofoil profile on a workstation in the DPO. The aim is to consolidate the lecture material and illustrate how the various design constraints compete in practice.

Advanced aerodynamics (4L, Dr J.P. Jarrett)

• Aerodynamic challenges of high-speed flight
• Airframe/Intake integration
• Stability of swept wing aircraft
• Practical swept wing design
• Delta wings
• Vertical take-off and landing

Aviation and the environment(6L, Prof. W. N. Dawes)

the environment
overview of atmospheric chemistry, fluid dynamics & mixing
the greenhouse effect; radiative forcing
airframe
aircraft range & endurance, the Breguet equation; ML/D
payload, fuel and structure weight; choice of fuel
why do airplanes fly at the altitude they do?
payload and fuel efficiency
engine
simple modelling of a high-bypass ratio turbofan engine
cycle efficiency & propulsive efficiency
trading production of NOx and CO2

Greener by Design(Coursework, Prof. W.N. Dawes)

The coursework consists of a choice of one from three case studies, based on the simple modelling above to study from the perspective of environmental impact the trade-offs associated with (A) design range;(B) cruise altitude;and (C) engine overall pressure ratio. It is intended that the case studies will be spreadsheet based.

OBJECTIVES

On completion of the course the student should:

• Have an appreciation of the aerodynamic factors likely to feature in the designs of new aircraft;
• Have an understanding of the behaviour of boundary layers over swept wings in compressible flow;
• Be able to estimate the position of laminar-turbulent transition;
• Be able to estimate wing drag, and to be familiar with techniques for avoiding turbulent flow;
• Have sufficient knowledge to be able to predict the different supersonic zones on a wing;
• Understand how the basic physics can be integrated into the design of an aircraft.
• Understand how to make design trade-offs
• Have a basic appreciation of the impact of aviation on the environment and possible responses.

REFERENCES

Please see the Booklist for Group A Courses for references for this module.

Last updated: September 2012
teaching-office@eng.cam.ac.uk