Ladder energy dissipater with doped gas device preposed

The invention relates to a stepped energy dissipater, which comprises steps arranged on a bottom slope and an aerating device positioned on the upstream of the steps. The aerating device is provided with four structural forms. In the first structural form, the aerating device is composed of a flip bucket, a vent hole and a vent shaft, in the second structural form, the aerating device is composed of a flip bucket, an aeration slot, a vent hole and a vent shaft, in the third structural form, the aerating device is composed of a flip bucket, a step-down floor, a vent hole and a vent shaft, and in the fourth structural form, the aerating device is composed of a flip bucket, a step-down floor, an aeration slot, a vent hole and a vent shaft. The energy dissipater can not only enhance the stepped energy dissipation rate, but also reduce or avoid the possibility of the cavitation corrosion and the damage to the steps, and thereby effectively solve the problems of the contradiction between the increase of the energy dissipation rate and the improvement of the cavitation corrosion and the damage resistance when an overflow spillway or an overflow dam surface is operated with large discharge per unit width.