Calculate Pressure Drag: Do-It-Yourself Wind/Water Tunnels?

In summary, for simple objects like a cylinder, there are analytical solutions available for calculating pressure drag. However, for more complex objects, such as a high powered rocket, there is no easy way to calculate the drag without the use of CFD software. Building a mini wind tunnel is possible with a vacuum cleaner and plexiglass, but the results may not be publishable. There are also free CFD programs available for those who do not have access to professional software.
  • #1
Shawnzyoo
105
0
Is there a way to calculate the pressure drag on objects?
without having to turn to CFD software?
thanks

also has anyone here ever built their own small wind/water tunnels for testing?
and how successful they were?
 
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  • #2
For simple objects, such as a cylinder and with some basic assumptions there exist some analytical solutions. Unfortunately for anything complex, we all know the pressure drag or drag due to lift depends on the lift. The lift is dependent on the ambient conditiosn and the the geometry and material of the object. So in the end there is no easy way to calculate the drag of any complex object withoutthe use of CFD
 
  • #3
thats what I was afraid of
are there any good free CFD progs to use?
i don't have access to progs like fluent
 
  • #4
What kind of object are you interetsed in? There are many closed form solutions out there.

It is easy building a mini windtunnel you just need a vacuum cleaner and some plexiglass. Probably not publishable results but good for home experiments or classroom projects.
 
  • #5
a high powered rocket is what I am doing
i have thought about building a windtunnel but i didn't think it would be nearly accurate enough for me
 

What is pressure drag?

Pressure drag is a type of drag force that occurs when an object moves through a fluid, such as air or water. It is caused by differences in pressure on the front and back of the object, which creates a force that opposes the motion of the object.

Why is it important to calculate pressure drag?

Calculating pressure drag is important because it allows us to understand and predict the effects of drag on an object's motion through a fluid. This is useful in designing more efficient and streamlined objects, such as airplanes or cars, and in understanding the forces that act on objects in nature, such as fish swimming through water.

What factors affect pressure drag?

The main factors that affect pressure drag are the shape and size of the object, the speed at which it is moving through the fluid, and the properties of the fluid itself (such as density and viscosity). The angle of the object in relation to the flow of the fluid also plays a role in pressure drag.

How can I calculate pressure drag using a do-it-yourself wind/water tunnel?

To calculate pressure drag using a do-it-yourself wind/water tunnel, you will need to measure the drag force acting on the object as it moves through the fluid. This can be done using a force sensor and a computer program that records the data. From there, you can use the drag force and other measurements, such as the object's speed and size, to calculate the pressure drag using equations from fluid dynamics.

What are some real-world applications of understanding pressure drag?

Understanding pressure drag has many real-world applications, including in aerodynamics, hydrodynamics, and sports. It is essential in designing efficient and streamlined vehicles, such as airplanes and boats, and in predicting the flight of projectiles. It is also important in sports such as cycling, skiing, and swimming, where minimizing drag can improve performance.

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