![using a pitot tube at stp using a pitot tube at stp](http://designer.home.xs4all.nl/models/su27-32/su-cocdetil9.jpg)
Where subscripts 1 and 2 represent any two points on a streamline. The result is V2 p1 p2 V2 1 1 1 gz1 5 1 2 1 gz2 ρ 2 ρ 2 Hence, M 5 0.236 and the assumption of incompressible flow is valid.Īpplications The Bernoulli equation can be applied between any two points on a streamline provided that the other three restrictions are satisfied. Pitot tic) (or the exteri tubes are often placed o or of airc n raft to in speed re dicate air lative to the aircra hence air ft, and craft spe ed relati ve to the air.Īt T 5 20 C, the speed of sound in air is 343 m/s. This prob lem illus tra tube to d etermine tes use of a pito t flow spe pitot-sta ed. P0 is the stagnation pressure at the tube opening where the speed has been reduced, without friction, to zero. Writing Bernoulli’s equation along the stagnation streamline (with Δz 5 0) yields Frictionless deceleration along stagnation streamline. Solution: Governing equation: Assumptions: The flowing fluid is air and the manometer liquid is mercury. Given: Find:Ī pitot tube inserted in a flow as shown. If the pressure difference is 30 mm of mercury, determine the flow speed. The static pressure is measured at the same location in the flow, using a wall pressure tap. The tube is inserted so that it points upstream into the flow and the pressure sensed by the tube is the stagnation pressure. The definition and calculation of the stagnation pressure for compressible flow will be discussed in Section 12.3.Ī pitot tube is inserted in an air flow (at STP) to measure the flow speed. (Note that when pB 6¼ pC, this procedure will give erroneous results.) Remember that the Bernoulli equation applies only for incompressible flow (Mach number M # 0.3).
Using a pitot tube at stp Pc#
In flow fields where the static pressure variation in the streamwise direction is small, the pitot-static tube may be used to infer the speed at point B in the flow by assuming pB 5 pC and using Eq. The inner tube is used to measure the stagnation pressure at point B, while the static pressure at C is sensed using the small holes in the outer tube. (The stem of the total head tube is placed downstream from the measurement location to minimize disturbance of the local flow.) Two probes often are combined, as in the pitot-static tube shown in Fig. Simultaneous measurement of stagnation and static pressures.Īs shown. (a) Total head tube used with wall static tap