(a) What is the drag? Give two examples for a drag force.
(b) How can you reduce the drag on something moving through the air?
(a) What is the drag? Give two examples for a drag force.
(b) How can you reduce the drag on something moving through the air?
(a) Drag Force. A drag force is the resistance force caused by the motion of a body through a fluid, such as water or air. A drag force acts opposite to the direction of the oncoming flow velocity. The first point of view for the cause of drag is the skin friction. As the solid object moves through the fluid, All the parts of the object come in contact with the fluid. If the surface of the solid is very rough and the fluid is a highly viscous fluid, there will be a huge amount of drag. On the other hand, when a smooth surface and a fluid of low viscosity comes in contact (with the shape being the same), a relatively low drag force is generated.
(b) To reduce the drag on something moving through the air one can:
- Make it more streamlined,
- Reduce its speed (very effective)'
- Reduce its cross-sectional area,
- Add boundary layer blowing,
- Suck the boundary layer.
- Coat it with a low friction layer (Teflon, wax).
- Go to higher, less dense air,
- Go to hotter air.
(a) Drag Force. A drag force is the resistance force caused by the motion of a body through a fluid, such as water or air. A drag force acts opposite to the direction of the oncoming flow velocity. The first point of view for the cause of drag is the skin friction. As the solid object moves through the fluid, All the parts of the object come in contact with the fluid. If the surface of the solid is very rough and the fluid is a highly viscous fluid, there will be a huge amount of drag. On the other hand, when a smooth surface and a fluid of low viscosity comes in contact (with the shape being the same), a relatively low drag force is generated.
(b) To reduce the drag on something moving through the air one can:
- Make it more streamlined,
- Reduce its speed (very effective)'
- Reduce its cross-sectional area,
- Add boundary layer blowing,
- Suck the boundary layer.
- Coat it with a low friction layer (Teflon, wax).
- Go to higher, less dense air,
- Go to hotter air.
