eng Ansari Education and Research Society Journal of Ultra Scientist of Physical Sciences August 2009 21 2 571 575 jusps-A 1225 article Ravindra Kumar (rkpal.maths@gmail.com 1 K.K. Singh 1 A.K. Sharma 1 Department of Maths, Agra College, (UP) INDIA <p style="text-align: justify;">The purpose of the present paper is to study the unsteady flow of visco-elastic Rivlin-Ericksen type fluid through porous medium in a long uniform confocal elliptical duct under the influence of an arbitrary time dependent pressure gradient. Mathieu functions have been used to obtain the exact solution of flow problem. Some particular cases for different pressure gradients have also been discussed in detail. We have used the notations of Mc Lachlan⁷&nbsp;as regard to Mathieu functions.</p> https://www.ultrascientist.org/paper/1225/ Rivlin Ericksen visco-elastic confocal elliptical ductu00a0