Effect Boundary Roughness on Rayleigh-Taylor Instability of a Couple-Stress Fluid

The effect of boundary roughness on Rayleigh-Taylor instability (RTI) of a couple–stress fluid layer bounded above a clear fluid and below by a rigid surface with roughness boundary is studied using linear stability analysis. Because of the growing importance of non-Newtonian fluids (Couple-stress fluid) in modern technology and industries as well as various practical applications investigations on such fluids are desirable. An expression for the growth rate of RTI is derived using suitable boundary and surface conditions in addition to couple-stress boundary conditions. From this it is clear that the effects of couple-stress parameter, roughness parameter and bond number play a significant role in maintaining the stability on the two fluid system.