Discussion of “Transcritical Flow due to Channel Contraction” by O. Castro-Orgaz, J. V. Giraldez, and J. L. Ayuso

The design of channel contraction is not obvious when transcritical or near-critical flows take place. The concept of critical flow conditions was first developed by Belanger (1828) and later expanded by Bakhmeteff (1912, 1932). Belanger and Bakhmeteff both defined the concept of critical flow in relation to the singularity of the backwater equation. Herein further applications of transcritical flow in channel contraction are discussed and a solution of the critical flow singularity is presented.