Aerodynamics - AE2-201
To develop an understanding of incompressible and compressible aerodynamics, and the basic prediction methods for aerofoil design at both low and high speed. It extends the incompressible and compressible analyses of the first year Aerodynamics and Thermodynamics courses respectively, and forms a direct link to the third year course in Aircraft Aerodynamics.
Aircraft Aerodynamics - AE3-301
This course covers the essential aircraft aerodynamics over a range of Reynolds numbers & Mach numbers. The course is divided in to two parts, one part focussing on incompressible aerodynamics, the second exploring compressible aerodynamics.
The aims for the incompressible aerodynamics part of the course are:
- Convey the essential fluid dynamics associated with aircraft flight at low Mach number. For the simple case of a thin-wing in incompressible flight, and by the use of a small-perturbation analysis, the Navier-Stokes equations can be reduced to the linear Laplace’s equation, which permits the linear superposition of simple solutions. Thus the effects of incidence, thickness and camber can be examined separately, and we confine our attention to thin wings of varying planforms, but making the important distinction between large and small aspect ratios. Large aspect-ratio wings are examined principally by using the distinction of bound and trailing vorticity, and in particular, by use of lifting-line theory – a “lumped-vortex” model. This is then modified to account for the effects of sweep. Slender wings are examined in a similar fashion, although there are some fundamental approximations.
- Viscous effects are accounted for by use of both laminar and turbulent boundary layer theory in two dimensions. Simple boundary layer solutions are sought, as well as solutions to the lifting-line equation. The physical aspects of separated flow on swept and slender wings are also examined.
The aims for the compressible aerodynamics part of the course are:
- To provide an introduction to available analytical and computational methods for the aerodynamic calculation of flow about aerofoils and wings based on the inviscid compressible fluid model. The non-linear character of flow discontinuities such as shocks is emphasised. The shock-expansion theory is applied to the calculation of aerofoils in supersonic flows. Effects of friction and heat-transfer on compressible flow are emphasised.
- The theory of characteristics (TOC) is then introduced to gain a mathematical insight onto the behaviour of a compressible inviscid flow. The TOC provides a numerical method for calculating unsteady 1-D isentropic flow and 2-D supersonic flow. In this last case the TOC leads to an elegant method for wind tunnel nozzle design.
- Concentrating in the aerodynamic aspects of compressible inviscid flow, the behaviour of the flow about aerofoils and wings is characterised in terms of the Mach number and the previous theory is used to discuss the feasibility and applicability of linear theories at the different regimes. The linearised theory of compressible flow is described and particular attention is given to the 2-D and 3-D subsonic similarity rules. The critical Mach number is used as a limit of the validity of the linearised theory of subsonic flow.