Obtaining drag force from pressure distribution

In summary, the speaker is trying to determine the drag force on a smooth cylinder at the exit plane of a wind tunnel. They have taken pressure measurements at regular intervals and have the freestream velocity and stagnation pressure. However, they are unsure how to use this data to find the drag force. With help, they found the drag coefficient for the large and small cylinders to be 0.71 and 1.07, respectively.
  • #1
IrishAlex
2
0
I'm trying to obtain the drag force acting on a smooth cylinder at the exit plane of a wind tunnel. I took measurements of pressure at regular degree intervals around the cylinder.

The pressure readings are in inches of water, and I know the freestream velocity and the stagnation pressure. I just don't know what to do with the data I have to obtain a value for drag force.
 
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  • #2
Thanks for all your help. I found Cp at all the points of pressure measurement, multiplied by cos of the angle of rotation, plotted the product versus angle of rotation and integrated from 0 to pi.

Turns out the drag coefficient for the large cylinder is about 0.71 and 1.07 for the small cylinder.
 

Related to Obtaining drag force from pressure distribution

1. What is drag force and why is it important?

Drag force is a force that opposes the motion of an object through a fluid, such as air or water. It is important because it affects the speed and efficiency of the object's movement, and is a crucial factor in the design and performance of many systems, such as airplanes, cars, and ships.

2. How is the pressure distribution related to drag force?

The pressure distribution around an object is directly related to its drag force. In general, an object experiences greater drag force when there is a larger difference in pressure between the front and back of the object.

3. What methods are used to obtain drag force from pressure distribution?

There are several methods that can be used to obtain drag force from pressure distribution. These include experimental measurements using pressure sensors, computational fluid dynamics simulations, and theoretical calculations using equations such as Bernoulli's principle.

4. Can an object's shape affect the drag force?

Yes, an object's shape can greatly affect the drag force it experiences. Objects with streamlined or aerodynamic shapes, such as airplanes, experience less drag force compared to objects with a less efficient shape, such as a cube.

5. How can understanding drag force help improve design and performance?

Understanding drag force is essential in designing efficient and high-performance systems. By minimizing drag force, engineers can increase the speed, maneuverability, and fuel efficiency of vehicles and other objects. It can also help identify potential problems and areas for improvement in existing designs.

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