FLOW AND STABILITY OF THREE-DIMENSIONAL ROTATING VISCOELASTIC JET

We consider rotationally driven nonlinear viscoelastic jet. In contrast to previous unrealistic planar studies with no gravity effect, we investigate here realistic three-dimensional jet with gravity effect. Using theoretical and computational methods, we develop models for such jet and its stability and determine the solutions. We find three-dimensional jet with gravity effect leads to faster and thinner jet. For jet arc length higher than its exit diameter, our calculation with typical parameter values shows that jet radius is smaller by a factor of more than 1.4 and jet speed is higher by factor of more than 2 as are compared to the exact planar jet counterpart results. Our linear stability of such jet uncovers new instability of the most critical three-dimensional spatiotemporal disturbance that grows in time very close to the three-dimensional jet exit but decays in space and can become stable for sufficiently far away from jet exit.