Study the Impact of an Exponentially Stretching Rate and Shape Factor of the Axisymmetric Bullet-Shaped Object on the Mixed Convection Boundary Layer Flow and Heat Transfer with Stream-Wise Coordinate and Viscous Dissipation
Authors: Ali Mohammad , Alim Md. Abdul 
Published: June 2022

The current work has been investigated the influence of the exponentially stretching rate and shapes factor of the axisymmetric bullet-shaped object on the mixed convection magnetohydrodynamic boundary layer flow and heat transfer with viscous dissipation, stream-wise coordinate, and
internal heat generation. The main goal of this problem is to discuss the effect of the surface shape and size, stream-wise coordinate, and also the exponential stretching factor of the bullet-shaped object on the fluid flow distribution. The novelty of the present work involved in the area
of recently developed numerical method to solve these highly nonlinear differential equations. The present analysis has been performed for both of the fixed (ε = 0) and moving (ε > 0) bullet-shaped object in the two cases of thinner (0 < s < 0.1) and thicker
(s ≥ 0.3) surfaces of the bullet-shaped object. It is noted that when ε = 0 means for a fixed bullet-shaped object in a moving fluid and while a moving bullet-shaped object in a fixed fluid represents when ε > 1. The governing equations have been converted
into a system of ODEs by using suitable local axisymmetric transformations and solved by applying the spectral quasi-linearization method. This method helps to identify the accuracy, validity, and convergence of the present numerical computations. The computations have been investigated by
the effects of different parameters on the flow field, wall friction, and heat transfer. The investigation depicts that the flow field and temperature do not converge the free stream condition asymptotically in the case of a thicker bullet-shaped object instead it intersects the axis with
a steep angle which is contradictory with the boundary layer theory and the boundary layer structure has no defined shape whereas in the case of a thinner bullet-shaped object (0 < s < 0.1) the ambient condition satisfies asymptotically and formed a definite boundary layer structure.
Heat transfer rate at the bullet-shaped object is negatively correlated with the magnetic parameter, Eckert number, heat generation parameter, and surface thickness parameter but positively correlated with the Prandtl number, location parameter, mixed convection parameter, and stretching ratio
parameter. The investigation represents that surface thickness parameter (shape and size) and stretching ratio parameter have a prominent effect on fluid flow properties and cannot be neglected. It is also noticed that the thinner bullet-shaped object acts as a good cooling conductor compared
to thicker bullet-shaped object and the wall friction can be reduced much when a thinner bullet-shaped object is used rather than the thicker bullet-shaped object in both types of moving or static bullet-shaped object (ε = 0.0 and ε = 0.2). The present analysis reveals
that the heat transfer and the friction factor will be helpful in industrial sectors such as a cooling device in nuclear reactors, automotive engineering, electronic engineering, biomedical engineering, control the cooling rate and quality of the final product.