Department of Pure Mathematics, Ferdowsi University of Mashhad (in cooperation with the Center of Excellence in Analysis on Algebraic Structures and Tusi Mathematical Research Group)Khayyam Journal of Mathematics2423-47888220220701Orthogonal spline collocation methods for 1D-parabolic problems with interfaces24326015471610.22034/kjm.2022.286589.2263ENSantosh KumarBhalDepartment of Mathematics, School of Applied Sciences, Centurion University of Technology and Management, Paralakhemundi, India0000-0001-8394-4821SnehalataBehuraDepartment of Mathematics, CIPET:IPT, Bhubaneswar-751024, India.Ashish KumarNandiMathematics Division, School of Advanced Sciences, Vellore Institute of Technology, Chennai, 600127, Tamil Nadu, India.Journal Article20210516Orthogonal spline collocation methods (OSC) are used to solve one dimensional heat conduction problems with interfaces. Cubic monomial basis functions are used to approximate the solution for spatial discretization and the Crank-Nicolson method for time stepping. Existence and uniqueness results are established for a discrete problem. This method is easily extended to monomials of higher degree. We present the results of experiments involving several examples which show the efficiency of OSC method. For both cubic and quartic basis functions, the results of numerical experiments demonstrate fourth-order accuracy in L∞ and L2 norms, and third-order accuracy in the<br />H1 norm. Moreover, sixth order superconvergence in nodal error of derivative of the OSC approximation for quartics is observed. OSC approach gives rise to almost block diagonal linear systems which are solved using standard software.http://www.kjm-math.org/article_154716_53417164f62805e6f80372cfaf7fd20d.pdf