What is the primary purpose of a wind tunnel in aerodynamics research?

• To measure lift and drag forces on models

• To test rocket propulsion systems

• To study soil erosion

• To simulate road traffic

Which type of wind tunnel is designed for testing aircraft at speeds greater than Mach 5?

• Subsonic

• Transonic

• Supersonic

• Hypersonic

In a subsonic wind tunnel, what is the main effect of reducing the cross-sectional area of the test section?

• Increasing velocity

• Increasing temperature

• Decreasing velocity

• Increasing density

In subsonic wind tunnels, what is the Mach number of the airflow in the test section?

• Mach number less than 1

• Mach number equal to 1

• Mach number greater than 1

• Mach number equal to 2

Which of the following is generally neglected in basic wind tunnel analysis?

• Compressible flow effects

• Friction losses

• Acoustic noise

• None of the above

Which section of a subsonic wind tunnel is responsible for slowing down the airflow and increasing the pressure after the test section?

• Diffuser

• Plenum chamber

• Throat

• Contraction section

In subsonic flow, what happens to velocity and pressure when the cross-sectional area decreases?

• Increase Mach number

• Increase velocity and reduce pressure

• Reduce velocity and increase pressure

• None of these

What is the purpose of the plenum chamber in a wind tunnel?

• To supply uniform airflow

• To increase pressure

• To slow down the airflow

• To create turbulence

In subsonic flow, what happens when the cross-sectional area of the tunnel increases?

• Larger area → Higher velocity

• Smaller area → Lower velocity

• Larger area → Lower velocity

• None of the above

Which of the following is an important consideration when scaling down a model for wind tunnel testing?

• Model size reduction

• Flow uniformity

• Flow visualization

• Data accuracy