ABSTRACT
In 1732 Henri de Pitot invented the pitot tube for the measurement of the flowing velocities of fluids. Pitot tubes detect the flowing velocity either at one point, at several inlet points into an averaging probe, or at many points across the cross section of a pipe or duct. The total pressure develops at the point where the flow is stagnated isentropically, which is assumed to occur at the tip of a pitot tube or at a specific point on a bluff body immersed in the stream. Such probes must be carefully aligned with respect to the direction of fluid flow, which is sometimes uncertain when turbulence exists. The pitot tube is made less sensitive to flow direction if the impact aperture has an internal bevel of about 15 degrees extending about 1.5 diameters into the tube.
