This discussion focuses on the application of Bernoulli's equation to ideal fluids in piezometric measurements. It establishes that for an inviscid fluid, the pressure remains constant along a horizontal pipe, resulting in zero height in piezometers, as the pressure at the base equals atmospheric pressure. In contrast, a viscous fluid experiences a pressure drop along the pipe, allowing fluid to rise in piezometers due to the pressure gradient. The conversation clarifies the conditions under which pressure variations occur and the implications for fluid dynamics in different scenarios.
PREREQUISITESFluid mechanics students, engineers working with hydraulic systems, and professionals involved in fluid dynamics analysis will benefit from this discussion.
Do you have a specific physical problem in mind that we can focus on (involving actual equipment and hardware)?fog37 said:1) I see how a fluid at rest and a fluid in steady motion are different situations. I guess I am wondering if the isotropic pressure, at the same spatial point in the liquid, would be higher if the fluid was at rest (not a stagnation point). How different would the pressure experienced by the liquid parcels be?
That's not what you have in post #26. You have an h instead of a z. h is measured downwards and z is measured upwards. Do you not see the difference? If the datum for both elevation and depth is taken at the upper (free) surface of the fluid, then ##h=-z## and ##p=-\rho g z = \rho g h##2) Ok, but if you take the equation in your post #29 (where ##v=0##, which implies a fluid at reset) and move the term ##\rho g z## on the righthand side, we get the equation $$P=const. - \rho g z$$, which is what I have in my post #26 (different from the correct expression for hydrostatic pressure)...