Aerodynamics for Engineers

The chapter begins with the basic thermodynamic concepts that form the basis of high-speed flow theory, including a basic physical understanding of the second law of thermodynamics. This results in the ability to use the isentropic flow relationships in analyzing the properties of a compressible flow field, which results in the ability to analyze flow in a stream tube, and understand how a converging–diverging nozzle works. The basic relations for determining the change in flow properties across shock waves and expansion fans are developed, which make it possible to analyze flow fields using shock and expansion calculation methods. The basic relations for viscous flow are developed, leading to the relations for calculating the local skin-friction coefficient for a compressible boundary layer. The reader will then be able to understand the cause and effect of shock–boundary layer and shock–shock interactions. Finally, concepts for how flight vehicles are tested in wind tunnels are developed, which explains why it is difficult to fully model full-scale flight characteristics.