Date of Award


Degree Type


Degree Name

Master of Engineering


Mechanical and Materials Engineering


Prof. Roger E. Khayat


The symmetric two-dimensional flow of a thin viscoelastic fluid jet emerging from a vertical channel is examined theoretically in this study. The fluid is assumed to be a polymeric solution, modeled following the Oldroyd-B constitutive equation. The influence of inertia, elasticity and gravity in the presence of surface tension is investigated for steady flow only. Special emphasis is placed on the initial stages ofjet development. The viscoelastic boundary-layer equations are solved by expanding the flow field in terms of orthonormal shape functions. In contrast to the commonly used depth-averaging technique, the proposed method predicts the shape of the free surface, as well as the velocity and stress components within the fluid. It was found that the jet reaches the same uniform thickness regardless of Reynolds number in the absence of gravity. However, the distance to reach the uniform thickness depends on inertia. Presence of gravity enhances the jet contraction and leads to possible jet break up. Presence of surface tension tends to prohibit the contraction and flatten the jet surface. In contrast to the Newtonian flow, viscoelastic flow displays uniform flow much farther from the channel exit. Swelling is observed as Deborah number increases. The velocity and stress components profiles suggest that elasticity tends to play different role to inertia. Surface tension tends to flatten the jet surface similar to the Newtonian jet, but the stress components are not affected much in the case of a viscoelastic jet. The numerical solution is validated with experiment and good qualitative agreement is achieved.



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.