Resultant force on pipe (Fluid Mechanics)

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Ronaldo95163
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Homework Statement


Posted in picture below

Homework Equations


Bernoulli's Equation
P/pg + v1^2/2g + z1 = P/pg + v2^2/pg + z2

The Attempt at a Solution


Posted in picture below

Wasn't sure if what I did was correct...still practising the topic itself
 
Attachments
  • Diagram of a horizontal Y-junction pipe with flow entering from the left in the main pipe, labelled P = 200 kPa, V = 2 m/s, D = 6 cm; the 30 degree branch is labelled D = 2 cm and the outlet D = 4 cm.
    Screenshot_2015-09-24-19-29-57~2.jpg
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  • Handwritten fluid mechanics working on lined paper: Bernoulli's equation for pressure at a pipe bend, summing x and y forces, momentum flux terms, and a force vector diagram with resultant F = 268.95 N at 50.7 degrees.
    20150924_200555.jpg
    29.6 KB · Views: 547
  • Handwritten fluid mechanics solution on lined paper: pipe junction sketch with flow rates and angle, continuity and momentum equations for V3 = 6 m/s, Bernoulli equation giving P2 = 197500 Pa, and boxed solution list.
    20150924_202355.jpg
    24.3 KB · Views: 557
The quality of your exhibits is very poor, but, as best I could tell, your approach is on target. But I wish I could see a cleaner rendition of your momentum balance.

Chet
 
Chestermiller said:
The quality of your exhibits is very poor, but, as best I could tell, your approach is on target. But I wish I could see a cleaner rendition of your momentum balance.

Chet
Sorry about that
I think it got messed up when it was uploading.

These are my cacluations for momentum

Im thinking that I was supposed to make the momentum in the y direction negative?
 
Attachments
  • Handwritten fluid mechanics working on lined paper: momentum balance equations in x and y directions for a pipe, with boxed results Fx = -257.4405 and Fy = 9.0745 pi kg m/s, and a resultant force vector calculation giving theta = 5.159 degrees.
    1443149835078-1161415095.jpg
    34.9 KB · Views: 552
Ronaldo95163 said:
Sorry about that
I think it got messed up when it was uploading.

These are my cacluations for momentum

Im thinking that I was supposed to make the momentum in the y direction negative?
I still can't read it. Did you remember to include the pressure forces on the fluid entering and leaving?
What you're trying to do is a momentum balance on the fluid passing through the y. The force of the fluid on the y is then minus the force of the y on the fluid.

Chet