Measurement of the dynamical free surface deformation in liquid bridges

We have designed and developed a new experimental procedure for investigating the dynamical free surface deformation due to Marangoni convection in liquid bridges on the basis of optical imaging. The images were formed by background illumination to give a silhouette effect, and recorded by a CCD camera with certain sampling rate. Global thresholding technique was used for processing the recorded digital images. The time-dependent behavior of the free surface was examined. Free surface displacements of sub-micron order were well determined by this method. The amplitudes and frequencies of the oscillations were measured for a wide range of applied temperature differences.