Abstract: By solving the three-dimensional incompressible Reynolds-averaged Navier-Stokes equations, numerical simulations of the viscous flow within a flush type intake duct of a waterjet under different motion conditions are carried out. Therein, the effects of the steering and reversing unit as well as the impeller shaft on the flow field are taken into account. The numerical results show that the static pressure under backward conditions with the reversing jet flow is the lowest, and the cavitations are most likely to occur within the intake duct. The flow field under forward conditions is less uniform because of the shaft, while the velocity uniformity under backward conditions is improved. The shaft rotation causes an asymmetric secondary flow above the shaft under all conditions. The pressure contours under backward conditions with the reversing jet flow are sensitive to the presence of the shaft. This study can provide some references for the design optimization of waterjet propulsion system.

Key words: waterjet, intake duct, viscous flow, numerical simulation