Abstract
A traveling-wave solution with coherent structures typical in channel flow is numerically obtained by employing Newton-Raphson method and continuation of solutions by smooth transformation homotopy. The artificial force term used in the continuation method is different from that in Waleffe (2003) [Phys. Fluids. 15 (6) 1517], while the solution seems to be finally converged to the same. By applying the method to the computational domain with a spanwise wavelength that is twice that of Waleffe's solution, we have found the subharmonic branches of the solution, that contain not a single structure but several structures with different scales.
