- #1
daniscp
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Is there any experiments I could do to prove that the Drag Coefficient of a Sphere is more or less 0.5 depending on the roughness of the sphere?
Experimental work to prove that the Drag Coefficient of a sphere is 0.5
- Thread starter daniscp
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In summary, the conversation discusses potential experiments that could be done to prove that the Drag Coefficient of a Sphere is 0.5, depending on the roughness of the sphere. The suggestion of using a wind tunnel or measuring the fall time of the sphere are mentioned, as well as using strain gauges and calculating the drag force using a pitot and flow velocity measurements. The person asking the question also clarifies that this is not a repost and they do have access to a wind tunnel.
- #2
Mech_Engineer
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The obvious question- do you have access to a wind tunnel?
Other than that, it might be possible to levitate the sphere in a vertical tube with air blowing through at its terminal velocity, or perhaps drop the sphere a long distance and measure its fall time very precisely, and compare that time to a calculated fall times with and without drag?
Other than that, it might be possible to levitate the sphere in a vertical tube with air blowing through at its terminal velocity, or perhaps drop the sphere a long distance and measure its fall time very precisely, and compare that time to a calculated fall times with and without drag?
- #3
Mech_Engineer
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I recognize your name now... Isn't this basically a repost of your previous thread?
- #4
daniscp
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Mech_Engineer said:
Yeah I have access to a wind tunnel...
It's not a repost since I've decided now to focus on proving that the drag coefficient of a sphere is 0.5. The only thing I need to think of is an experiment to measure the drag force...but can't come up with one
- #5
brewnog
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How about some strain gauges?
- #6
jaap de vries
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You can measure the flow velocity behind the ball using a pitot at several locations that you can calculate the momentum change which is equal to the drag force so you divide that by D*rho*V^2*0.5 and you will probably get a value near 0.5 (plus or minus 0.5).
1. What is a Drag Coefficient?
The Drag Coefficient is a dimensionless quantity that represents the resistance of an object moving through a fluid, such as air or water.
2. Why is the Drag Coefficient important?
The Drag Coefficient is an important factor in determining the aerodynamic or hydrodynamic performance of an object. It can affect the speed, stability, and energy efficiency of the object.
3. How can you measure the Drag Coefficient of a sphere?
To measure the Drag Coefficient of a sphere, you can conduct experiments in a controlled environment, such as a wind tunnel or water tank, and record the forces acting on the sphere at different velocities.
4. What is the significance of proving that the Drag Coefficient of a sphere is 0.5?
The Drag Coefficient of 0.5 for a sphere is considered a universal constant and is used as a benchmark for comparison with other objects. It also helps in predicting the aerodynamic or hydrodynamic behavior of other objects with similar shape and size.
5. How can you use the experimental data to determine the Drag Coefficient of a sphere?
By analyzing the forces acting on the sphere at different velocities and calculating the ratio of the drag force to the dynamic pressure, you can determine the Drag Coefficient of the sphere using the equation Cd = Fd / (0.5 * ρ * v^2 * A), where Cd is the Drag Coefficient, Fd is the drag force, ρ is the density of the fluid, v is the velocity, and A is the cross-sectional area of the sphere.
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