What is the coefficient of drag for a cylinder?
What is the coefficient of drag for 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 |
What is reference area in drag?
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 area?
For larger objects (such as a baseball) moving at a velocity v in air, the drag force is given by FD=12CρAv2 F D = 1 2 C ρ A v 2 , where C is the drag coefficient (typical values are given in Table 1), A is the area of the object facing the fluid, and ρ is the fluid density.
What are the dimensions of the drag coefficient?
In fluid dynamics, the drag coefficient has no dimensions. It is a dimensionless quantity. Drag coefficient is used to quantify the resistance of an object in a fluid environment.
How do you calculate drag coefficient?
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.
How is drag measured?
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. For given air conditions, shape, and inclination of the object, we must determine a value for Cd to determine drag.
How does area affect drag coefficient?
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 the dimension for drag coefficient?
1. What is the dimension for drag coefficient? Explanation: In fluid dynamics, the drag coefficient has no dimensions. It is a dimensionless quantity.
How do you calculate projectile motion with air resistance?
Mathematically, the resistive force represented by the vector F can be written as F=-f(v) u, where u=V/|V| is the unit vector along the direction of the velocity V. The minus sign guarantees that the air resistance acting on the projectile is always opposite to the direction of its velocity.
How do you calculate the reference area from the drag coefficient?
The drag coefficient cannot be defined unless the reference area is also defined. If you know the drag coefficient (or look it up in a table) you will know how to measure the reference area. You cannot calculate reference area from drag coefficient unless you also know drag force, speed and velocity.
Is the drag coefficient independent of the shape’s dimensions?
Drag coefficients for the solid hemisphere, hollow hemisphere, and cube are independent of dimensions or Reynolds number. The drag coefficient for the solid cone, ellipsoid, thin annular disk, solid cylinder, and solid square rod have drag coefficients that are functions of the shape’s dimensions.
How do you calculate drag coefficient for annular disk?
For the thin annular disk, A = π (D o2 – D 2) / 4. The drag coefficients (C) used in our calculation are from Blevins (2003). Drag coefficients for the solid hemisphere, hollow hemisphere, and cube are independent of dimensions or Reynolds number.
What are the drag coefficients for some common body types?
The drag coefficients for some common bodies are indicated below: Type of Object Drag Coefficient – cd – Frontal Area Passenger Train 1.8 frontal area Motorcycle and rider 1.8 frontal area Long flat plate at 90 deg 1.98 Rectangular box 2.1
