In the present study, free convective, laminar flow of Casson fluid is investigated numerically over a nonlinear stretched sheet to observe the characteristics of heat transfer in the presence of Newtonian heating. Nonlinear differential equations are derived from the present flow by utilizing the appropriate transformations. Thereafter, for the linear stretching case, an exact solution is applied for the momentum equation, and for the nonlinear stretching case, a convergent numerical technique, SRM, is applied. Computations of SRM and exact solutions are displayed through graphs. For various physical parameters, variation in velocity profile is observed by means of numerical computations and presented graphically. For checking the accuracy and convergence of the proposed method, outcomes are validated with the available outcomes in the literature and compared. The outcomes demonstrate that the velocity profile is reduced for the nonlinear stretching parameter effect, and, with increasing Pr, the temperature is decreased and there is a reduction in the thickness of the thermal boundary layer. K E Y W O R D SCasson fluid, exact solutions, Newtonian heating, nonlinear stretching sheet, SRM

In the current work boundary layer flow of Casson fluid over a stretched sheet is considered to analyze the heat transfer analysis in presence of viscous dissipation. The study of Casson fluid is the best study to analyze the nature of non-Newtonian fluid. The set ordinary equations are derived from the governing equations of the flow along with boundary conditions. The transformed coupled ordinary differential equations are solved numerically by using the spectral relaxation method. Later the numerical solutions are compared with exact solutions. The consequences of governing parameters on dimensionless quantities like velocity, temperature, friction factor and local Nusselt numbers are shown and discussed. Here the result shows that the Casson fluid has a propensity to decrease the velocity of the fluid due to its higher viscidness. And the fluid of relatively small Prandtl number has high temperature in the occurrence of viscous dissipation. Applications of such type of problems are obtained in the control of complex fluid materials significant to energy and biomedical systems.