STABILITY OF TWO SUPERPOSED VISCOUS-VISCOELASTIC FLUIDS by Pardeep KUMAR and Roshan LAL

The Ray leigh-Tay lor in sta bil ity of a New to nian vis cous fluid over ly ing a Rivlin-Ericksen viscoelastic fluid is con sid ered. Upon ap pli ca tion of nor-mal mode tech nique, the dis per sion re la tion is ob tained. As in both New to-nian vis cous-vis cous flu ids the sys tem is sta ble in the po ten tially sta ble case and un sta ble in the po ten tially un sta ble case, this holds for the pres ent prob lem also. The be hav iour of growth rates with re spect to ki ne matic vis-cos ity and ki ne matic viscoelasticity pa ram e ters are ex am ined nu mer i cally and it is found that both ki ne matic vis cos ity and ki ne matic viscoelasticity have sta bi liz ing ef fect. Key words: Ray leigh-Tay lor in sta bil ity, nor mal mode tech nique, linearized the ory, Rivlin-Ericksen viscoelastic flui