The influence of structure parameters on the pressure characteristics of spillway tunnel

Abstract Cavitation is one of the key challenges of high-head and large-discharge spillway tunnel. The high-speed flow may cause a sudden drop in pressure in the case that spillway tunnel built without suitable shape or smooth surface. Meanwhile, the complex flow pattern accelerates the occurrence of cavitation. The anti-arc section is usually set at the end of spillway tunnel for trajectory bucket type energy dissipation, and a horizontal section may be set upstream of the anti-arc section to adapt to local topography. It’s necessary to conduct in-depth research on the pressure characteristics of horizontal section and anti-arc section to prevent cavitation. In this paper, the pressure distribution along the spillway tunnel is calculated using VOF method. The influences of the length of horizontal section, the radius of anti-arc section and arc section are studied. The results show that the horizontal section suffers low pressure. Reducing the radius of anti-arc section is effective for raising the pressure in horizontal section. However, the minimum pressure cannot be raised when the length is larger than a certain value.