In this paper, a novel approach, namely, the linearization-based approach of homotopy analysis method, to analytically treat non-linear time-fractional PDEs is proposed. The presented approach suggests a new optimized structure of the homotopy series solution based on a linear approximation of the non-linear problem. A comparative study between the proposed approach and standard homotopy analysis approach is illustrated by solving two examples involving non-linear time-fractional parabolic PDEs. The performed numerical simulations demonstrate that the linearization-based approach reduces the computational complexity and improves the performance of the homotopy analysis method. KEYWORDS homotopy analysis method, linearization-based approach of HAM, series solution, time-fractional parabolic PDE MSC CLASSIFICATION 26A33; 34E10; 35K15; 41A58
INTRODUCTIONThe homotopy analysis method (HAM), introduced in previous studies, 1-5 is an approximation technique used to analytically solve various types of non-linear differential equations. This method utilizes homotopy in order to deform a continuous mapping with free parameters of an initial guessed approximation to the exact solution of the considered problem. The actual success of HAM is greatly depends on the appropriate selection of these parameters. The theory and applications of the method has been developed recently to deal with numerous types of non-linear problems in applied science fields (see previous studies 6-20 and references therein). In previous studies, 21-40 the application of the method has been expanded to deal with non-linear fractional differential models. These extensions, which generalize the HAM, were successfully implemented to get precise approximate solutions of non-linear time-and space-time fractional differential equations accurately and conveniently. Furthermore, some approaches which are designed optimally to improve the efficiency of the HAM have been introduced. 41-51 These approaches present techniques by which one may select best or appropriate parameters. As observed in other work, 41-51 the employment of the optimal parameters within HAM accelerate the rapid convergence of the HAM series solutions.The flexibility of the HAM in selecting the auxiliary control parameter, the initial guess, the auxiliary linear operator and the auxiliary function is one of the main merits of the method. Liao 1 mentioned that it is necessary to introduce mathematical results that propose new ideas for the appropriate selection of the auxiliary control parameter, the initial guess and the auxiliary linear operator. Therefore, the main objective of this paper is to implement Taylor series approximation of the non-linear equation in order to extract an optimized linear operator. Then, to construct a favourable homotopy Math Meth Appl Sci. 2019;42:7222-7232.