Go Back   Physics Help Forum > High School and Pre-University Physics Help > Thermodynamics and Fluid Mechanics

Thermodynamics and Fluid Mechanics Thermodynamics and Fluid Mechanics Physics Help Forum

Reply
 
LinkBack Thread Tools Display Modes
Old Dec 1st 2015, 10:44 AM   #1
Junior Member
 
Join Date: Nov 2015
Posts: 3
Continuity Equation

I have attached a problem. I think the answer is v1=v2 because of the continuity equation A1*v1=A2*v2. Because it has a uniform cross section A1=A2 so v1=v2.

It seems like this problem gives a lot of extra information though. I don't need to use Bernoulli's equation for this correct?

Thanks in advance!
Attached Files
File Type: pdf Physics Problem.pdf (63.7 KB, 12 views)
beika is offline   Reply With Quote
Old Dec 1st 2015, 11:25 AM   #2
Physics Team
 
ChipB's Avatar
 
Join Date: Jun 2010
Location: Morristown, NJ USA
Posts: 2,347
Remember that the "A" in your equation is the cross-section area of the fluid, which may not be the same as the cross-section of the pipe. Clearly the fluid picks up kinetic energy as it descends down the incline, so v2 > v1. Which means A2 < A1. Hence if the fluid entering the pipe completely fills the crosss-section of the pipe, then when it exits the fluid's cross-sectional area is less than the area of the pipe. Bottom line: yes, use Bernoulli.
ChipB is offline   Reply With Quote
Old Feb 4th 2016, 11:45 AM   #3
Junior Member
 
Join Date: Feb 2016
Posts: 16
continuity

A1*V1=A2*V2 this is true for one dimensional case (v=v(x) but here you have v=v(x,y) and then continuity becomes du/dx+dv/dy=0
use the energy eqn (Bernoulli )
shai is offline   Reply With Quote
Reply

  Physics Help Forum > High School and Pre-University Physics Help > Thermodynamics and Fluid Mechanics

Tags
continuity, equation



Thread Tools
Display Modes


Similar Physics Forum Discussions
Thread Thread Starter Forum Replies Last Post
Bernoulli Equation guaiamum Thermodynamics and Fluid Mechanics 7 Aug 1st 2016 04:26 AM
continuity equation.. alexandros87 Thermodynamics and Fluid Mechanics 10 Nov 22nd 2015 03:56 PM
The incompressible continuity equation Devlan Advanced Mechanics 2 Jun 2nd 2014 01:20 PM
cylindrical continuity eq using cartesian substitute. psyclone Advanced Mechanics 0 Jul 26th 2013 07:09 PM
equation petdem Thermodynamics and Fluid Mechanics 8 Feb 15th 2010 05:51 AM


Facebook Twitter Google+ RSS Feed