Transient analysis of the fluid flow on a pumpjet propulsor

This work discussed the transient characteristic of PJP and gave a comparative analysis between steady and transient simulations. The simulations employed Reynolds-averaged Navier-Stokes equations (RANSE) method with a focus on the transient flow field and tip clearance effect. The mutual interference between rotor and stator does not lead to a massive difference in PJP whole open water performance. It causes remarkable changes in stator and duct, and the increasing of tip clearance enhances the changes. The exciting force on blades can not be ignored and represents a different variation between rotor and stator with the effects of advance ratio or tip clearance and possesses a characteristics frequency corresponded to blade passing frequency (BPF) and their harmonics. The exciting force intensity mainly embodies in BPF. The stator mainly has better recycling on rotor blade wake, and the recycling mainly acts on circumference velocity. Comparing with axial velocity, which shares almost the whole energy in PJP wake, both the circumference velocity and radial velocity include a little. Tip sweeping vortex and tip leakage vortex are the typical vortices in PJP. Tip leakage vortex plays a vital role in the stator flow field and PJP wake.