Supersonic Flow Measurement
Pressure Measurement using Mercury Manometers
Since the stagnation pressure in the upstream pressure vessel is quite high, a multi-column manometer has been used rather than one very long single column.
The mercury columns are joined by incompressible water columns.
The final measure of stagnation pressure can be determined by addition of the mercury column heights and then subtracting the effect of the weight of water.
Static pressure along the nozzle is obtained using a multi-tube manometer. Individual ports are connected in sequence. The axial position of the static pressure measurement points is shown in the previous nozzle diagram.
Since the pressures drop below atmospheric then the values should be read from the manometer as follows.
