Effect of spin slip conditions on Couette-Poiseuille flow of couple stress fluid between parallel plates.

In the current paper, we investigate the effect of spin slip conditions for the Couette-Poiseuille flow of a couple stress fluid between two parallel plates. In the study, the motion of the fluid is considered to be steady, incompressible and unidirectional. At the interface between the fluid and the plates (both the upper and lower), we consider the non-zero tangential and couple stress spin slip relationships as boundary conditions. We present analytical expressions for the velocity profile, volume flow rate, vorticity, and couple stresses. This paper discusses the numerical influence of the spin slip parameter, velocity slip parameter, couple stress parameter, and pressure gradient on the velocity, vorticity, couple stresses, and volume flow rate. Our results show that the presence of the spin slip parameter reduces the velocity, couple stress and volume flow rate of the fluid, while it enhances the vorticity. The limiting cases for each problem align well with previously published results regarding the vanishing of couple stresses at the boundaries. This research helps both researchers and engineers in understanding how to control the conditions to achieve an efficient fluid flow, particularly in applications involving couple stress effects, such as microfluidics systems, lubrication technology, and polymeric suspensions. [ABSTRACT FROM AUTHOR]