Fluid flow problem with the momentum balance equation

[abstracted6]

All problem info, and my work is done in the attached pdf.

Basically, I'm not sure that I have done it correctly.

 

[LawrenceC]

What is the formula for the area of a circle in terms of diameter?

 

[abstracted6]

Ooops

So the answer is then:


F_p = -$\rho$v_j²$\frac{\pi}{4}$(D₁² - D₂²)

 

[LawrenceC]

Looks good to me.

 

[rude man]

Comment: interesting problem; case where change in momentum is vΔm instead of the usual mΔv.