Abstract
The series of flows around the piers in draft tubes of bulb turbines were investigated. The flow fields were assumed to be steady incompressible turbulent flows. The primary factor responsible for total pressure loss in draft tubes was investigated based on the data obtained. Well-known horseshoe-shaped vortices were observed at the leading edges of piers as a result of simulations. These vortex structures were found to greatly contribute to total pressure loss in the present cases. Simulations on several variously shaped draft tubes were carried out and these suggested slight modifications to draft tubes would effectively curtail total pressure loss around a pier.
