Undular jump formations in very large channels

In this paper, undular hydraulic jumps in very large channel (channel width equal to 4.0 m) for low Rey-nolds number have been investigated. Jumps with very high aspect ratios are very rare in literature, and, therefore, experimental works are necessary. The main aims are (i) analyzing the lateral shock wave in order to verify the experimental validity of the shock wave theory in very large channel, (ii) analyzing the flow conditions of undular jumps in very large channels. The main results are the following: (i) the pres-ence of well developed lateral shock wave similar to those of oblique jumps were observed; (ii) the com-parison of the experimental results and the theoretical ones show that the classical shock wave theory is confirmed, taking into account the experimental errors; (iii) the literature law of the wave height of first wave crest was confirmed also in the case of very large channels