Modified kinematic viscosity model for 3D-Casson fluid flow within boundary layer formed on a surface at absolute zero Naramgari Sandeep a, ⁎, Olubode Kolade Koriko b , Isaac Lare Animasaun b a Fluid Dynamics Division, VIT University, Vellore 632014, India b Department of Mathematical Sci., Federal University of Technology, Akure, Ondo State, Nigeria abstract article info Article history: Received 4 April 2016 Accepted 14 June 2016 Available online 20 June 2016 Three-dimensional Casson fluid flow towards a stagnation-point and a surface on which the heat energy falls at lower limit of thermodynamic temperature scale in the presence of cross diffusion is investigated. The flow is in- duced by a pressure-gradient and impulsive. We modified the space-dependent heat source in such a way that the uniform distribution of internal heat-source, also satisfies the wall and free stream temperatures. Also, the in- fluence of heat energy on plastic dynamic viscosity is investigated by considering the relationship between the intermolecular forces holding the molecules of Casson fluid. The modified kinematic viscosity model suitable for the flow is presented. The governing equations are non-dimensionalized by using suitable similarity transfor- mation, which unravels the behavior of the fluid flow at short-time and long-time period. The effects of pertinent parameters on the flow, heat and mass transfer is discussed with the help of graphs. Local Nusselt and Sherwood numbers are computed and presented through tables. Obtained results are validated and found a favorable agree- ment. It is observed that the Soret and Dufour parameters have tendency to control the thermal and concentra- tion boundary layers as well as the heat and mass transfer rate. © 2016 Elsevier B.V. All rights reserved. Keywords: Impulsive Intermolecular forces Casson fluid Variable plastic dynamic viscosity Absolute-zero of temperature 1. Introduction In the field of fluid mechanics, the number of space coordinate re- quired to describe fluid flow can either be referred to as one-, two- or three-dimensional flow. The best description of any physical flow is generally three-dimensional. Although, this often lead to stronger non-linear coupled governing equations and thus appears more difficult to solve. The problem of mixed convection 3-dimensional flow over a horizontal surface due to both pressure gradient and impulsive of fluid layer at free stream provides one of the most basic scenarios for heat and mass transfer theory and thus is of considerable theoretical and practical interest. The mathematical problem briefly mentioned above was addressed in 1951 by Howarth [1]. The equation of boundary layer flow in the vicinity of stagnation point on a general three-dimen- sional surface was investigated and it was reported that after applying the theory of Ludwig Prandtl [2], the momentum equations would be reduced to a pair of simultaneous ordinary third-order differential equations containing a single parameter “c” which is determined by the mainstream flow. This nature of solution is based on the fact that the mainstream outside the boundary layer is irrotational. Later, Patankar and Spalding [3] presented a calculation procedure for describ- ing the transport processes in three-dimensional flows characterized by the presence of one coordinate in which physical influences are exerted in only one direction. The general approach to the classification of ele- mentary three dimensional flow patterns is explained in Chong et al. [4]. All these contributions to the body of knowledge can be easily de- duced in the similarity variables (η) for scaling and parametrization of dimensional governing equations. Nadeem et al. [5] deliberated on magnetohydrodynamic three-dimensional Casson fluid flow past a po- rous linear stretching sheet and assumed that the horizontal sheet is stretched with two different linear velocities along the plane. Modern experimental and computational fluid mechanics is increasingly con- cerned with the three-dimensional nature of fluid motion. In view of this, Ahmed et al. [6] presented modeling of three-dimensional channel flow in a chemically-reacting fluid between two long vertical parallel flat plates in the presence of a transverse magnetic field and its analyt- ical and numerical solutions. In the published articles on boundary layer together with heat trans- fer, the wall temperature is often assumed to be highly greater than that of the free stream. In the field of fluid dynamics, this contribution to- gether with heat source/sink term in the energy equation are to be properly considered due to its accuracy and validity in modeling heat distribution within the fluid domain in real life. It is worth noticing that the upper fluid layer tends to posses higher magnitude of heat Journal of Molecular Liquids 221 (2016) xxx–xxx ⁎ Corresponding author. E-mail addresses: sandeep@vit.ac.in (N. Sandeep), okkoriko@yahoo.com (O.K. Koriko), anizakph2007@gmail.com (I.L. Animasaun). MOLLIQ-05956; No of Pages 10 http://dx.doi.org/10.1016/j.molliq.2016.06.049 0167-7322/© 2016 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Journal of Molecular Liquids journal homepage: www.elsevier.com/locate/molliq Please cite this article as: N. Sandeep, et al., Modified kinematic viscosity model for 3D-Casson fluid flow within boundary layer formed on a surface at absolute zero, J. Mol. Liq. (2016), http://dx.doi.org/10.1016/j.molliq.2016.06.049 Pages 1197–1206