ABSTRACT
It is instructive to review briey the principles of uid dynamics in order to understand Pitot tube theory and applications. Consider, for example, a constant-density uid owing steadily without friction through the simple device shown in Figure 62.1. If it is assumed that there is no heat being added and no sha work being produced by the uid, a simple expression can be developed to describe this ow:
p
w
v
g z
p
w
v
2 2 2
+ + = + +
(62.1)
where p1, v1, z1 are the pressure, velocity, and elevation at the inlet, respectively p2, v2, z2 are the pressure, velocity, and elevation at the outlet, respectively w = ρg is the specic weight of the uid ρ is the density g = 9.80665 m s−2
Equation 62.1 is the well-known Bernoulli equation. e following example will demonstrate the use of Equation 62.1 and lead to a discussion of the theory of Pitot tubes.
