Aerodynamics 2

Question 1

Explain 2 reasons why drag arises - even in the absence of flow separation?

Answer 1

1. The direction action of skin friction.
2. The growth of the boundary layer very slightly changes the effective shape of the body seen by the stream. This changes the pressure distribution. This induces a pressure drag.

Question 2

Define Kelvin’s Circulation Theorem

Answer 2

It states that in an inviscid flow with uniform density, the circulation around a closed loop which moves with the fluid is constant.