Based on an analysis of causes of cavitation damages to the downstream at the end of ogee section in the spillway tunnel of open channel,it is pointed out that the aeration measure for sidewall protection nearby the downstream of ogee section should be paid much attention in aerator design.Large-scale model tests were performed to study whether the cavitation alleviation of downstream sidewall in ogee section can be realized by enhancement of the aeration capacity of upstream aerator.The results show that t...