The venturi effect causes an increase in velocity and decrease in pressure in a converging duct, with the opposite occurring in a diverging duct, at subsonic speeds. At supersonic speeds, the venturi effect is reversed. The speed of sound decreases with decreasing temperature and can be calculated based on temperature. Mach number is the ratio of object speed to the local speed of sound. Oblique, normal, and expansion shockwaves occur at supersonic speeds depending on the angle of the surface and change in airflow velocity and pressure. Design features like vortex generators, swept wings, and thinner wings can increase the critical Mach number and reduce the effects of shockwaves.

1. Venturi EffectsSubsonicConverging

2. Increasing velocity

3. Decreasing pressure