Answer:
1.693 feet
Explanation:
We have given Q = 90 gpm
We know that 1 cubic feet per second = 443.833 gpm
So 90 gpm will be equal to [tex]\frac{90}{443.833}=0.202\frac{ft^3}{sec}[/tex]
Let d is the diameter of the pipe then [tex]V_{avg}=\frac{Q}{A}=\frac{0.2}{\frac{\pi }{4}d^2}=\frac{0.255}{d^2}[/tex]
We know that for pipe flow critical Reynolds number =2300
So [tex]\frac{V_{avg}d}{\nu }=2300[/tex]
Value of [tex]\nu[/tex] is [tex]6.55\times 10^{-5}[/tex] given in question
So [tex]\frac{0.255\times d}{d^2\times 6.5\times 10^{-5}}=2300[/tex]
d=1.693 feet
