The kinetic energy of the moving fluid is equal to the pressure energy within the tube. However for a closed pipe in which the water is flowing under pressure, it is necessary to measure the static pressure also. For an open channel, a simple pitot tube will serve the purpose. Thus, a pitot tube is an instrument which conveniently isolates the kinetic energy of a moving fluid. BASIC CONCEPT The pitot tube can be used to measure the velocity of water in an open channel as well as in a closed pipe. If you recall, BernoulliвЂ™s principle stated that a finite volume of fluid will have the same amount of energy It will be neither created nor destroyed.

At some point in the tube, the fluid becomes stationary and all of the kinetic energy possessed by the fluid is transformed into pressure energy.Д«ernoulliвЂ™s equation can be used to calculate the pressure at the stagnation point, which can then be converted into kinetic energy to find the velocity of the flow. It is widely used to determine the airspeed of an aircraft, water speed of a boat, and to measure liquid, air and gas flow velocities in certain industrial applications. When the fluid enters the pitot tube, it is forced to come to a stop. Additional details concerning pitot tube traverses, tube construction and applicaВ tions of tube traverses are given by Streeter (1961) and Dean (1953). They are an important part of an airplane, where they are used to provide the pilot with in-flight velocity measurements. Record both the residual and pitot gauge readings. For accurate pitot gauge readings, the pitot tube should be held downstream and in the center of the nozzle. Residual pressure and pitot gauge readings must be taken simultaneously. ITABAR-pitot tube sensors, see sample Fig 1. After the residual pressure read from the outlet cap stabilizes, take readings at each hydrant using a pitot gauge. Pitot tubes are small, right angle shaped tubes that can measure the velocity of a fluid. The measuring principle of the pitot tube utilizes the differences between the pressure ridge on the upstream side of a bluff body and the static pressure on its down stream side.

Calculating velocity using a pitot tube