Measurements of the length of the zone of flow establishment in a jet using a Laser Doppler Anemometer

The length of the zone of flow establishment in a submerged, turbulent, buoyant, axisymmetric jet issuing into a quiescent ambient fluid was investigated using a Laser Doppler Anemometer and microthermocouple probe. Also, velocity and temperature profiles were measured through various cross-sections of the jet; A 3-dimensional traversing mechanism with feedback and interface circuitry was constructed and then controlled by an 80286 microcomputer. Software for computer aided data acquisition was written for the Laser Doppler Anemometer and traversing mechanism and was executed on the 80286 microcomputer; An experimental setup was constructed to form axisymmetric jets and to allow for the addition of heat, seed particles, and the control of velocity and temperature. The jet nozzle was made in such a way as to allow for flow measurements at angles of inclination from 0 to 90 degrees; The work conducted for this experimental thesis expands the existing data on jets. A new formula for the zone of flow establishment was developed that relates its length to the Reynolds number in the nozzle. The length of the zone of flow establishment in an axisymmetric, vertical jet was found to vary according to the formula:{dollar}{dollar}\eqalign{&{S\sb{ZFE}\over D}\approx{5.03{\cdot}Re\sb{D}\over Re\sb{D}-361}\cr\cr&45