In this paper, the minimum computational domain size for correctly capturing Taylor-Görtler (TG) vortices in a streamwise-rotating plane channel is investigated using direct numerical simulations (DNS). To assess the effect of system rotation on the scales of TG vortices, a wide-range of rotation numbers have been tested, varying from Ro
= 7.5 to 150. The highest rotation number tested in the current research far exceeds that reported in literature (Ro
= 30) by Yang et al. (2010). In order to precisely capture TG vorticies, DNS has been performed in a very large box domain of 512πh ×2h×8πh, where h is one-half the channel height. A two-layer pattern of TG vortices is observed, and the scales of TG vortices are quantified using the pre-multiplied two-dimensional energy spectra.