Qin, DenghuiDenghuiQinPan, GuangGuangPanShi, YaoYaoShiHuang, QiaogaoQiaogaoHuang2021-03-032021-03-032019-0911th International Workshop on Ship and Marine Hydrodynamics (IWSH2019), Paper 15http://hdl.handle.net/11420/8984The sawtooth duct noise reduction technology is used for underwater noise reduction of Pumpjet Propulsor (PJP). Flow around the PJP is solved using Detached-Eddy-Simulation (DES) model, while noise is predicted based on Ffowcs-Williams and Hawkings equation. Results show that the sawtooth duct can reduce the sound pressure level of PJP over the frequency range 100-5000 Hz, although it will result in water efficiency loss at low J cases. The sawtooth duct makes the axial velocity distribution of PJP outflow more uniform and reduces the TKE value at the wake region of PJP. The maximum water efficiency is reduced about 2% by sawtooth duct, and the open water efficiency at low J case gradually decreases with the increase of the sawtooth inclination angle. Significantly, the sawtooth duct reduce the overall sound pressure level about 3.82-7.17 dB, while causes the efficiency loss about 1.67%-2.56% at the design point. The sawtooth duct with sawtooth inclination angle 10°has the most great noise reduction about 7.17 dB with only 1.93% openwater efficiency loss at the design point of PJP.enhttp://rightsstatements.org/vocab/InC/1.0/Pumpjet propulsorUnderwater noise reductionSawtooth ductInclination angleTechnikIngenieurwissenschaftenConference Paper10.15480/882.332410.15480/882.3324Fluiddynamik und Schiffstheorie M-8Conference Paper