What is the reference area for drag force?
What is the reference area for drag force?
The reference area depends on what type of drag coefficient is being measured. For automobiles and many other objects, the reference area is the projected frontal area of the vehicle. This may not necessarily be the cross sectional area of the vehicle, depending on where the cross section is taken.
How do you calculate drag on a cylinder?
The drag equation states that drag D is equal to the drag coefficient Cd times the density r times half of the velocity V squared times the reference area A.
What is the drag coefficient of a cylinder?
The drag coefficient quantifies the drag or resistance of an object in a fluid environment.
| Type of Object | Drag Coefficient – cd – |
|---|---|
| Wires and cables | 1.0 – 1.3 |
| Person (upright position) | 1.0 – 1.3 |
| Hollow semi-cylinder opposite stream | 1.2 |
| Ski jumper | 1.2 – 1.3 |
How does surface area relate to drag?
The total aerodynamic force is equal to the pressure times the surface area around the body. Drag is the component of this force along the flight direction. Like the other aerodynamic force, lift, the drag is directly proportional to the area of the object. Doubling the area doubles the drag.
What is planform area?
The planform area is the area of the wing as viewed from above the wing, looking along the “lift” direction. It is a flat plane, and is NOT the total surface area (top and bottom) of the entire wing, although it is almost half that number for most wings.
What is the cross sectional area of a cylinder?
The cross-sectional area of a cylinder is equal to the area of a circle if cut parallel to the circular base. The cross-sectional area is the area of a two-dimensional shape that is obtained when a three-dimensional object – such as a cylinder – is sliced perpendicular to some specified axis at a point.
How is drag coefficient calculated?
The drag coefficient Cd is equal to the drag D divided by the quantity: density r times half the velocity V squared times the reference area A. The drag coefficient then expresses the ratio of the drag force to the force produced by the dynamic pressure times the area.
What is coefficient of lift and drag?
The lift to drag ratio (L/D) is the amount of lift generated by a wing or airfoil compared to its drag. The lift/drag ratio is used to express the relation between lift and drag and is determined by dividing the lift coefficient by the drag coefficient, CL/CD. A ratio of L/D indicates airfoil efficiency.
What is the relationship between the drag force and diameter?
For most large objects such as bicyclists, cars, and baseballs not moving too slowly, the magnitude of the drag force FD is found to be proportional to the square of the speed of the object. We can write this relationship mathematically as FD∝v2 F D ∝ v 2 .
How does surface area affect velocity?
The position in which the object falls changes the surface area and in turn changes the terminal velocity. If the object has a greater surface area it will have more room for air resistance to work on it. There will be a greater upward force and a smaller terminal velocity.