Would CD change for a cylinder if the

[Vanselena]

If the surface was completely hydrophobic vs normal skin drag? If it changed would it be significant in an object with a 7:1 ratio?

Thank you for your responses!

 

[Vanselena]

If the surface was completely hydrophobic vs normal skin drag? If it changed would it be significant in an object with a 7:1 ratio?

Thank you for your responses!

Forgot to mention the object would be under water.

 

[sir-pinski]

The coefficient of drag (CD) is a measure of the resistance an object experiences as it moves through a fluid, such as air or water. It is affected by various factors, including the shape and surface characteristics of the object. In the case of a cylinder, the CD would indeed change if the surface was completely hydrophobic (water-repelling) compared to normal skin drag.

A hydrophobic surface would create a layer of air around the cylinder, reducing the contact between the cylinder and the fluid. This would result in a lower CD, as there is less resistance for the fluid to overcome. On the other hand, a normal skin drag would create a thin layer of water around the cylinder, increasing the contact between the cylinder and the fluid and resulting in a higher CD.

In an object with a 7:1 ratio, the change in CD would still be significant, regardless of whether the surface was hydrophobic or not. This is because the ratio refers to the length-to-diameter ratio of the object, and not its surface characteristics. Therefore, the shape of the object would still play a major role in determining the CD, and a change in surface characteristics would result in a noticeable difference in drag.

In conclusion, the CD for a cylinder would change depending on the surface characteristics, and this change would be significant in an object with a 7:1 ratio. However, the exact magnitude of the change would depend on other factors such as the speed and viscosity of the fluid, and would need to be determined through experimentation.