“…Such equations have been generalized to the more relevant case of non‐isentropic flows by Fortunato and Napolitano[8], where an implicit point‐Gauss‐Seidel method has also been developed, which, however, requires too many iterations to converge. Alternatively, the merits of the fast Euler solver in the COIN variant version have been proven in[9], which provides the extension of such a methodology to three‐ dimensional flows, in order to compute subsonic internal flows accurately and efficiently. However, the three‐dimensional results presented in [9] refer to a simple geometry, discretized using cylindrical co‐ordinates; no comparison has been done because there are no other theoretical or experimental results available on the same test case.…”