| Hydraulic experiments of double-row bars under steady flow and unsteady flow conditions were conducted. The wavelength and bar height became almost constant after fully developed when the crest of bars appeared on the water surface. The geometrical characteristics of double-row bars under unsteady flow conditions are significantly different from that under steady flow conditions. This difference is related with duration time of flood. When the duration time is short、 the difference becomes large. According to Fourier spectrum analysis、 α20 is an important factor of generating ’self-formed stream channel’. |
