Unsteady and Three Dimensional PTV Measurements of Flow Structure in a Suction Pump

We attempt to reveal the unsteady three‐dimensional flow structure in a suction sump with the vertical‐wet‐pit‐pump configuration. In the present study, we consider the simultaneous measurement of a three‐dimensional particle tracking velocimetry (3D‐PTV) with another velocimetry, that is, an ultrasonic velocity profiler (UVP), using common tracer particles. This simultaneous measurement is expected to be a suitable method for the accuracy check of the 3D‐PTV. At first, we have successfully found the suitable condition for simultaneous measurements with high accuracy. Then, we have revealed the concerning unsteady three‐dimensional flow structure at various instants, quantitatively.