The experimental unit consists of two tapered inserts with which a gradual contraction of the measuring section in the wind tunnel is created. The dynamic and static pressure are measured using a Pitotstatic tube. During the experiments, the Pitotstatic tube is moved from the start of the contraction to the narrowest point, in this way the pressure as a function of position is measured. The apertures are fixed to the side walls of the measuring section using bolts, the Pitotstatic tube is placed in an opening on the bottom of the measuring section and moved along a slot in this position. The position of the probe can be read off in a scale beside the slot.
To indicate the pressure, the following units are optionally available: inclined tube manometer included in HM 170, differential pressure manometer HM 170.53, electronic pressure measurement HM 170.55 or system for data acquisition HM 170.60.