Study of triple diffusive convection in non newtonian liquids

Abstract

This thesis presents the study of triple diffusive convection in two nonNewtonian liquids couple stress liquid and viscoelastic liquid of type Oldroyd-B in the presence of external constraints like rotation, gravity modulation and temperature modulation. Linear stability analysis provides the stability condition of stationary and oscillatory convection and the resultant eigen function describes the newlineconvective flow. However, linear analysis can neither help to examine the rate newlineof heat and mass transfer nor provides information on the convection newlineamplitudes. Therefore, it is also important to do nonlinear analysis. In view of newlinethis, all the problems considered in this thesis are studied for both linear and newlinenonlinear cases. The eigen value arising in the linear case for the problems newlinewithout modulation is solved by normal mode technique whereas for the problems with modulation is solved by perturbation method by adopting Venezian approach. The nonlinear study is done by using Ginzburg Landau newlinemodel for the problems with couple stress liquid whereas the nonlinear study is done by truncated representation of Fourier series by Lorenz model for the problems with viscoelastic Oldroyd-B liquid. The present study has wide range of applications in material processing, solidification of alloys, underground spreading of chemical pollutants, petroleum reservoirs, cooling of electronic devices, thermal insulation newlinematerial, crystal growth, transport of chemical substances, solar receivers, newlineinjection moulding, chemical industries, nuclear industries, bioengineering, newlineoceanography, meteorology, astrophysics, geophysics and so on. The extensive description of wide-ranging applications of triple diffusive convection in non-Newtonian liquids is accountable for the motivation of this thesis. The following four problems are carried out in this thesis: (i) EFFECT OF ROTATION ON TRIPLE DIFFUSIVE CONVECTION IN COUPLE STRESS LIQUID The effect of rotation on triple diffusive convection in couple newlinestress liquid is considered.