ENTROPY GENERATION RATE IN UNSTEADY BUOYANCY-DRIVEN HYDROMAGNETIC COUPLE STRESS FLUID FLOW THROUGH A POROUS CHANNEL

Abstract

In this paper, the entropy generation rate in unsteady buoyancy-driven hydromagnetic couple stress fluid flow through a porous channel has been investigated. The partial differential equations are converted into their corresponding dimensionless equivalence, including the prescribed initial boundary conditions. These equations were solved using the Adomian decomposition method and the behaviour of some pertinent fluid variables, such as velocity, temperature, entropy generation rate and the irreversibility ratio were examined and discussed for different parameters of interest, which include, the Grashof number, the Hartmann’s number, the Reynolds number, the Brinkman number and the couple stress parameter. It was found that the entropy generation rate in the fluid model largely depends on the intermolecular forces between the fluid parcels. This has accounted for the observed increase in the entropy generation rate with respect to the couple stress parameter. Other observed entropy generation rate trends found their cause to the internal phenomenon in the fluid, though may be triggered by other forces such as the buoyancy and the Lorentz forces. Graphs are shown to illustrate the findings.