Understanding Aerodynamic Drag

What are the two components into which a drag force can be divided?

• Weight and thrust

• Thrust and lift

• Pressure drag and friction drag

• Lift and weight

What causes wall shear stresses?

• Frictional forces due to fluid viscosity

• The object's speed through the fluid

• Turbulence in the fluid

• Pressure differences around the object

At what angle does flow separation occur for a smooth sphere in laminar flow?

• 90 degrees

• 100 degrees

• 120 degrees

• 80 degrees

What is the effect of turbulence on the boundary layer in terms of flow separation?

• It reduces the boundary layer thickness

• It delays flow separation

• It causes immediate separation

• It has no effect

Why are golf balls designed with dimples?

• To make them look unique

• To increase their weight

• To increase their speed

• To reduce pressure drag by delaying flow separation

What is the primary goal of Hybrid Laminar Flow Control?

• To increase turbulence

• To delay the onset of turbulence

• To reduce the fluid's viscosity

• To increase the fluid's density

How much could artificial shark skin reduce the total drag force on a commercial airliner?

• 2%

• 1%

• 5%

• 10%

What does the drag coefficient (C-D) represent in the drag equation?

• The fluid's density

• The object's speed through the fluid

• Complex parameters like geometry and flow regime

• The reference area of the object

What happens to the drag coefficient of a sphere at very low Reynolds numbers?

• It increases

• It is defined as 24 divided by Reynolds number

• It decreases

• It remains constant

What is Stokes' Law used for?

• To calculate terminal velocity of a sphere in fluid at low Reynolds numbers

• To calculate the lift force on an airplane wing

• To measure the fluid's density

• To increase drag force on an object