Theoretical question- fluid flow from high to low energy
Theoretical question- fluid flow from high to low energy
(OP)
I know that fluid flows from areas of high energy to low energy, and not necessarily from high to low pressure. If you look at flow through a horizontal pipe that expands to a wider cross-section, some of the velocity head is converted into pressure head, which causes the pressure to be higher downstream. What confuses me is when Bernoulli's principle is stated as "In a flow of constant energy, when fluid experiences a decrease in velocity, it experiences an increase in pressure. If there is constant energy at all points in the flow, what exactly is driving the flow?
I know that clearly there must be a pump or something in the system, but the statements 1) fluid flows from areas of high energy to low energy and 2) Bernoulli's principle applies to flows of constant energy, seem to be contradictory to me.
Thanks
I know that clearly there must be a pump or something in the system, but the statements 1) fluid flows from areas of high energy to low energy and 2) Bernoulli's principle applies to flows of constant energy, seem to be contradictory to me.
Thanks





RE: Theoretical question- fluid flow from high to low energy
Look at this link
http://www.efm.leeds.ac.uk/CIVE/CIVE1400/Section3/...
RE: Theoretical question- fluid flow from high to low energy
What confuses me is that in section 2 on Bernoulli's principle, the total energy upstream is equal to the total energy downstream. What then, is meant when it is said that "fluid flows from regions of high energy to regions of low energy". How can there be flow if there is no difference in energy?
RE: Theoretical question- fluid flow from high to low energy
In practice their are losses, the basis for no loss of energy is an assumption, just like when you release a ball from height the energy changes from potential energy to kinetic energy, if you assume no energy is lost the ball just keeps bouncing but in real life that doesn't happen, the ball comes to rest.
So using the Bernoulli equation just gives an estimate of velocity, pressure at a particular point in a system, the formula can be modified to include losses and obtain a better estimate.
RE: Theoretical question- fluid flow from high to low energy
RE: Theoretical question- fluid flow from high to low energy
http://www.google.co.uk/url?sa=t&rct=j&q=&...
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RE: Theoretical question- fluid flow from high to low energy