In this paper we use an adaptive second-order Godunov scheme with front tracking algorithm to carry out two-dimensional numerical simulation of gaseous detonation in a channel. For the chemical kinetics, a single-step Arrhenius law is utilized. Initiation of detonation performs with a one dimensional planar blast wave as an initial condition. The one dimensional detonation is perturbed by placing a disturbance in the initial density. The structure of the front appears as detonation propagates in the channel. The front structure, that includes triple points, transverse waves, incident shock, and Mach stem, is investigated in this study. Cellular structure of detonation that is created by tracking of triple points, is observed. In long time propagation, only one cell across the channel, with a cell size of 10 units length, is formed. The convex curvature of the first half of a cell, as well as the concave curvature in the second half, is also observed in the present simulation.