Abstract
Measurement of dynamic surface deformation (DSD) is important for full understanding of oscillatory mechanisms of Marangoni convection in a liquid bridge. A novel method based on electronic speckle pattern interferometry (ESPI) is developed here. ESPI is widely used for displacement measurement of optically rough surfaces. The present system expands the capability of ESPI so as to measure specular liquid surfaces. Time sequence phase method is adopted for phase evaluation of specklegrams, which enables the method to measure dynamic displacement of deformed liquid surface with sensitivity of λ/4. Frequency analysis and comparison with previous data of DSD of liquid-bridge free surface are presented.
