98 / 2025-04-24 12:56:01

Morphodynamic equilibrium of alternate bar dynamics under repeated hydrographs

alternate bars, unsteady discharge, morphodynamic equilibrium

Discharge unsteadiness plays a key role in the dynamics of alternate bars, however, how migrating alternate bars determine their shape under unsteady discharge conditions, especially in the long-term, is still unclear. In this study, we numerically investigate long-term behaviors of migrating alternate bars subject to repeated hydrographs. For this, the same discharge variation but different hydrograph cycles were tested. The results show that even under unsteady flow conditions, specific combinations of hydrograph cycles and discharge variations result in an equilibrium state of migrating alternate bars (i.e., non-time dependent wavelength and migration period). This may be a unique feature of the alternate bar morphodynamics, since dynamic equilibrium state arising from steady discharge counterparts is time-dependent feature.