G-Jitter effect on heat and mass transfer of three-dimensional stagnation point nanofluid flow

Abstract

The study of fluid motion in fluid mechanics is useful in many engineering applications. Fundamental studies based on physics law on fluid motion could be done by mathematical formulation. Effects based on thermal energy such as heat source and heat absorber with its transferring mode can also be formulated into a mathematical system. Due to this reason, a boundary layer nanofluid flow near a stagnation point region of a three-dimensional body is studied in this thesis. Here, nanofluid containing copper nanoparticles and hybrid nanofluid containing copper and alumina nanoparticles with water as a base fluid are considered. In addition, a microgravitational field environment known as g-jitter is also considered. The main purpose of this study is to investigate theoretically the effect of thermal radiation and heat generation on fluid characteristics, heat transfer behaviour, and concentration distribution of the fluid flow system. In this study, the mathematical models that govern the fluid flow consist of continuity, momentum, energy, and concentration equations. These nonlinear partial differential equations are initially reduced into a dimensionless system of equations using the similarity transformation technique. The resulting dimensionless governing systems are then solved numerically using the Keller-box method. The numerical values of the skin friction coefficients, Nusselt number, and Sherwood number as well as the velocity, temperature, and concentration profiles are obtained for various values of the curvature ratio, amplitude of modulation, frequency of oscillation, nanoparticle volume fraction, heat generation parameter and thermal radiation parameter. The results from the analysis in relation to the studied physical parameters are graphically displayed and validated by comparing them to those of previous studies. The current study shows that the curvature parameter had a significant effect on the skin friction coefficient where planar and axisymmetric stagnation point flow occurred in a specified range of this parameter. On the other hand, increasing the modulation's amplitude causes all the physical quantities to fluctuate. It is observed that, when a higher frequency of oscillation is induced, the physical quantities are seen to be reduced. The addition of a small amount of copper nanoparticle in the fluid results in enhancement of conductivity of the thermal, as demonstrated by the Nusselt number. However, a contradictory behaviour was noticed on Sherwood number as copper nanoparticle was considered in the fluid problem. The internal heat generation has caused the temperature profile to increase, while the heat flux to decrease. Also, thermal radiation is found to improve the rate of heat transfer. Moreover, the addition of other nanoparticles which are alumina, further increased the thermal characteristic of the fluid system.