- #1
Euan2007
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Drag Coefficient out by a factor of 10, can anyone help??
Im doing an experiment on the drag of a sphere and am trying to work out the drag coefficient. From looking at data online this should be around 0.5 (its a smooth sphere). Using a wind tunnel I measured the drag for various sizes of spheres and wind speeds. An example of one of my results is
Drag - 0.68N
Wind Speed - 7.8m/s
Radius of Sphere - 0.0371m
Then, using the formula
Drag Coefficent = (2 x Drag) / Area x Wind Speed^2 x Density of Air
Having measured the room temperature to be 22 degrees celcius I took the density of air to be 1.204kg/m^3 and the projected frontal area was calculated using pi x r^2
But this equals 5.039! so could anyone point out where I am going wrong?? I am 90% sure all of my values are correct. Thanks in advance for any help :)
Im doing an experiment on the drag of a sphere and am trying to work out the drag coefficient. From looking at data online this should be around 0.5 (its a smooth sphere). Using a wind tunnel I measured the drag for various sizes of spheres and wind speeds. An example of one of my results is
Drag - 0.68N
Wind Speed - 7.8m/s
Radius of Sphere - 0.0371m
Then, using the formula
Drag Coefficent = (2 x Drag) / Area x Wind Speed^2 x Density of Air
Having measured the room temperature to be 22 degrees celcius I took the density of air to be 1.204kg/m^3 and the projected frontal area was calculated using pi x r^2
But this equals 5.039! so could anyone point out where I am going wrong?? I am 90% sure all of my values are correct. Thanks in advance for any help :)