Fluid flows over a smooth cylinder. The diameter of the cylinder is D and the length normal to the flow direction is L. The drag coefficient is defined as: The drag coefficient is essentially constant with a value of 1.1 in the range of Reynolds numbers of 103 to 105. In this range, at a velocity of 2 m/s the drag force is 3 N. When the velocity is doubled to 4 m/s the drag force is:

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nuuk nuuk · Answer 1 · 2019-12-18T11:09:59+01:00

Answer:

Explanation:

Given

Coefficient of drag [tex]C_d=1.1[/tex]

Reynolds number [tex]Re.no.=103 to 105[/tex]

velocity [tex]v=2 m/s [/tex]

[tex]F_d=3 N[/tex]

if velocity if 2v i.e. [tex]4 m/s [/tex]

[tex]F_d=\frac{1}{2}C_d\rho A v^2----1[/tex]

keeping other factors as constant

[tex]F'_d=\frac{1}{2}C_d\rho A (2v)^2----2[/tex]

dividing 1 and 2

[tex]\frac{F_d}{F'_d}=\frac{v^2}{2v^2}[/tex]

[tex]F'_d=4F_d[/tex]

[tex]F'_d=4\times 3=12 N[/tex]