Angled measuring device for determining the total pressure, i.e. the overall figure for the static and dynamic pressure associated with a fluid flowing at a subsonic rate. The pitot tube consists of a tube at a 90° angle, whose arm lies parallel to the direction of the flow (Figure P 9). Pressure measured with this kind of open tube will change in line with the angle, since dynamic pressure only acts in the direction of the flow. In order to avoid , the open area for the pitot tube must therefore be perpendicular to the velocity.
Figure P 9: Measuring total pressure with the pitot tube: a) With the U-shaped tube for a gas flow; b) Measuring a fluid