Considering the lack of research on the ventilation characteristics of open flow spillway tunnels under high flow velocity conditions, based on a 50 m/s high-speed jet test device, this paper investigated the effects of flow velocity, ventilation tunnel area, and relative height of spillway tunnels on the ventilation volume and wind speed distribution in ventilation tunnels. By analyzing 44 sets of prototype observation data and 28 sets of experimental data, an empirical formula for calculating ventilation at high flow rates was proposed. The results show that the measured value of ventilation is 2.1-9.6 times of the standard value when the water flow velocity is 18.0-37.2 m/s. As the area of the ventilation tunnel increases, the rate of increase in ventilation volume gradually decreases, and the distribution of wind speed inside the ventilation tunnel is related to the area of the ventilation tunnel. The ventilation volume first increases and then decreases with the increase of the height of the spillway tunnel, and the change in the relative height of the spillway does not change the wind speed distribution characteristics. The calculated ventilation value by the improved formula is relatively close to the actual measurement value, with 3/4 of the data within the 20% error line range. Research results can provide guidance for engineering practice.

ventilation volume  /  high velocity flow  /  open flow in spillway tunnel  /  ventilation tunnel