The discussion centers on the treatment of pressure differences at points P1 and P2 in the context of Bernoulli's equation for incompressible fluids. Participants clarify that the author assumes equal pressure at both points due to their selection of surface height values, which leads to the cancellation of pressure terms in the energy equation. The confusion arises from the dimensional differences between pressure and energy, and the necessity of dividing by ρg to simplify the equation. Ultimately, the conclusion is that the pressure difference is ignored because the chosen points are at the same elevation, resulting in equal pressures.
PREREQUISITESStudents of fluid mechanics, engineers working with fluid systems, and anyone seeking to understand the principles of energy conservation in incompressible fluid flow.
Pressure and energy are dimensionally different. How would you propose to take pressure into account for an energy equation involving incompressible fluid?foo9008 said:
sorry , why the author did not take the P/ y into the calculation ? where y = ρgharuspex said:
The 2+ and 1+ are the potential energy terms. It is a bit confusing because the author has divided out ρg everywhere.foo9008 said:
after dividing the ρg why there is no P to be taken into the calculation ? the author assume P1 and P2 as same pressure? why ?haruspex said:
Bernoulli's equation refers to identified points in the streamline. The author's choice of height values (1, 2) indicates the points being chosen are on the surface, so the pressure is the same. If instead you pick points at the bottom of the stream then the heights are the same and the pressures are different, but the equation turns out the same.foo9008 said:
so do you mean the author choose point 1 and2 on the surface??haruspex said:
It seems that way.foo9008 said:
