Making analogy between fluid mechanical and electrical system

Micko

Hi,
Because of pictures that are drawn, I find easier to make question completely in pdf document.
Thanks for help and understanding

Attached Files

Fluid-electrical analogy.pdf (7.6 KB, 122 views)

OlderDan

I'm sure this is not a complete answer to your question, but pressure in moving fluids is governed by Bernoulli's Equation

http://www.princeton.edu/~asmits/Bic...Bernoulli.html

There will be pressure differences in fluids depending on velocity and effects of gravity.

Micko

OlderDan, I have read about Bernoulli equation but I'm still confused about how analogy can be performed.
Main question is if fluid circuit is a system with distribuited parameters i.e. pressure drop occurs continually with length of a pipeline. I think so, and that's why I doubt this analogy with electrical circuit will give good results in wider band of applications.

moo

I think you've taken the analogy a bit too far. The pressure/volume analogy of volts/current is used mainly for a more easily understood example of something you can't see (electricity). The properties are similar, not identical.

Btw, technically the voltage won't be exactly the same at B and C, because it's farther from A to B than A to C, so there is a wee bit more voltage drop at B.

moo
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Micko

I agree, but the difference will be negligible because resistors used in this example usually have resistance that is much greater than resistance of line, and model implicitely assumes that all resistance is concentrated in resistors, so line resistance is 0. Since el. mag wave transfer at speed close to spped of light, voltage difference is negligible. Difference can be spoted in case of distances that can be compared with el.mag. wave length. On the other hand, in fluid circuit, there is always a pressure drop across pipeline . I'm interested to learn what happens when two different pipes (different diameters) connects in same point.