Author(s): L. Chiapponi; S. Longo
Linked Author(s): Luca Chiapponi
Keywords: Free surface; Turbulence; Hot film; Hot wire
Abstract: In this work the analysis of the interaction between turbulence and free surface is detailed. The phenomenon takes place in many natural flows and industrial processes. In the present experiments turbulence is generated by a vertically oscillating grid moving beneath the free surface. Fluid velocity has been measured through a hot film anemometer and the free surface elevation is measured by an ultrasonic sensor based on flight-time. Integral length scales and several turbulence estimators have been computed. Aiming to detect the source effects of turbulence near the free surface, the correlation between free surface elevation and the underneath flow velocity has been studied, and the time lag between turbulence and free surface has been evaluated. A resonance regime was observed, with turbulence excited by free surface growing at a specific frequency of the grid.
Year: 2011