Particle-Imaging Velocimetry and Pressure Measurements of the Turbulent Flows Inside the Intake Duct

The present study mainly treats the flow measurement for the intake duct of a water-jet propulsion equipment using stereoscopic particle image velocimetry (SPIV) technique. To obtain clear flow field information in the intake duct, the authors have developed a suitable SPIV calibration method and used a time filter to preprocess images. The velocity distributions in an intake duct is investigated at the flow rate ranging from 0–35 m³/h by an independently designed test rig, which is composed of an open circulating water tank, a pump, a control valve and other measuring sensors. The pressure transducers are also used to measure the pressure fluctuations at two typical positions near the lip of the intake duct. The velocity distributions at the midplane of the intake duct depict that there is a jet flow due to the presence of duct lip, and a strong separation flow is induced between the jet and the duct wall. The experimental results are useful to give a clear insight into the flow behaviors inside the intake, and show the reason of the flow distortion at the outlet of intake duct. Moreover, some guidance can be provided for the application of SPIV in the intake duct.