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I would like to ask you that why pressure drop is constant through pipe? How can we know that dP/dx=constant?
Thank you.
If it's an incompressible fluid, how does the fluid know that the conditions in one part of the pipe are different from another part of the pipe?
The average fluid velocity is the same everywhere.
If the fluid velocity is constant throughout the pipe, then everything else about the flow must also be constant, including the axial pressure gradient. What other possibility is there?
What is your existing background in fluid mechanics? Have you ever taken a course in the subject?
Try reading the first few chapters of Transport Phenomena by Bird, Stewart, and Lightfoot.I do not know what other possibility is but I want to study it. Under what topics of fluid mechanics, can I find this situation. And would you like to explain with what equation or from where do we know that if fluid velocity is constant then all other things should be constant. This means that all other things only the function of velocity as well.
So, I will study more but I need guidance.
Thank you.
What if the substance is a gas (axially varying velocity) or if the temperature is varying axially (axially varying viscosity). The the pressure gradient is not constant for these situations. Do you still maintain that this is the definition of the the pressure loss?The equation posted is the definition of pressure loss over the length at a given velocity.. (Initial pressure-final pressure)/length...
I agree. But it's certainly not a definition.I'd say so... the formula given doesn't account for any variation of other parameters...
If you wanted a formula to include different flow rates, viscosities, pressures, compressability, etc it would get complicated really quickly..
As presented, at a given pressure, flow, and viscosity, you can find the pressure drop per unit length.
If it's an incompressible fluid, how does the fluid know that the conditions in one part of the pipe are different from another part of the pipe? The average fluid velocity is the same everywhere.