(Fig. 22d) (C) Pitot tube: In such a device, part of the flow is made stagnant so that the entire KE of the fluid is converted into pressure–energy. A small opening is made in the device, parallel to the flow, where the pressure is the same as the fluid pressure. (Fig. 22e) Apply Bernoulli’s equation between 1 and 1’           (along the same–streamline; flow is parallel to opening )  Static pressure Apply Bernoulli’s equation between 1and 2 But,  Therefore,  By measuring the difference between stagnation and static pressures, one can calculate the velocity and the volumetric flow rate.