Velocity-field measurements in a dam-break flow using a PTV Voronoï imaging technique

摘要

A dam-break flow is an example of an extremely transient free-surface flow with various time and space scales. The importance of studying this type of flow is directly connected with the risk assessment of a dam and with the effects of such a catastrophe on human activities in the valley downstream. In this paper, an experimental study of the dam-break flow is presented. While a great part existing studies about dam-break flows are focused on variables such as the water-front velocity and the water level, the present paper is focused on the measurement of velocity profiles over the whole flow depth within the dam-break wave. For such study and due to the characteristics of the flow itself, image acquisition techniques were used. The velocity field was obtained by means of a Particle Tracking Velocimetry (PTV) algorithm based on Voronoï patterns’ matching. A comparison with the application of a PIV algorithm to the raw data is provided. Finally, results for the velocity profiles and water elevation are presented and discussed for two different flow conditions.