We investigate purely elastic flow instabilities in the almost ideal planar stagnation point elongational flow field generated by a microfluidic optimized-shape cross-slot extensional rheometer (OSCER). We use time-resolved flow velocimetry and full-field birefringence microscopy to study the behavior of a series of well-characterized viscoelastic polymer solutions under conditions of low fluid...

Research involving the interaction of flow with morphological instability during directional solidification of binary alloys is reviewed. In general, flow may arise during the solidification process from thermal and solutal buoyancy, changes in density upon solidification, thermocapillary forces at free boundaries, or external forcing of the system. We focus primarily on the last of these, givi...

This work discusses experimentally the hydrodynamic instabilities of an oriented nematic film contained in a plane Poiseuille flow cell such that the director is initially perpendicular to the velocity and velocity gradient. Homogeneous instabilities having a uniform distortion in the plane of the boundary plates are obtained with or without distortion of the flow profile. The thresholds are an...