(a, top) Diffraction pattern of a water jet with initial diameter 100 µm and flow rate 2.235 ml min−1 before the onset of jet instability [peak 1 of Fig. 4(a)] and (a, bottom) after the onset of jet instability [peak 7 of Fig. 4(a)]. (b) Scattering patterns of region I for a water jet exiting from a circular nozzle with diameter 100 µm and flow rate 2.235 ml min−1 at the maxima of the integrated intensity of Fig. 4(a). The continuous lines represent the fitting results of a power law onto the data. The upper dotted line is the theoretical curve for the refraction from a cylinder [equation (4)]. The lower dotted curve represents the theoretical curve for the refraction from spheres [equation (8)]. (c) Power law exponent as a function of the position along the jet showing the change from the refraction contribution of a cylinder to that of a droplet. The dotted line is a guide for the eye.