Experimental investigation of capillary instability: results on jet stimulated by pressure modulations

We investigate the behaviour of a liquid jet stimulated by pressure disturbances using a photometric measurement of the jet shadow width. Two apparatuses involving lights of different nature are utilized and measurements are taken from the exit of the nozzle to drop breakoff for different operating conditions. Fourier analysis is applied to characterize the spatial evolution of the jet shape. In contrast to previous studies where only amplitudes of the Fourier modes are reported, phase shifts are also recovered for low and high initial perturbations. We show that the spatial reconstruction of the jet from the temporal Fourier analysis at different abscissae is in excellent agreement with the experimental profilesThis paper has benefited from stimulating discussions with A. Spohn. The authors wish to thank the Management of Toxot Science & Applications for permission to publish this work. They extend their appreciation to the Centre National de la Recherche Scientifique (Contracts No. 509721 and 509776) and to the Ministère de l'Enseignement Supérieur et de la Recherche (Grant No. 92 P 0645) for partially supporting this study. Thanks are due to J.L. Bély and C. Marteau for their technical assistance. Finally the authors are indebted to the referees for their valuable comments.