Prediction of cavitating propeller underwater radiated noise using RANS & DES-based hybrid method

Abstract

This study focuses on the prediction of the hydrodynamic and hydroacoustic performance of a cavitating marine propeller in open water condition using Reynolds-averaged Navier-Stokes (RANS) and Detached Eddy Simulation (DES) solvers. The effectiveness of the methods is investigated for the recently introduced benchmark propeller that belongs to the research vessel 'The Princess Royal'. The main emphasis of the study is to examine the capabilities of the RANS and DES solvers for predicting the hydrodynamic performance of a propeller in the presence of sheet and tip vortex cavitation (TVC). In the numerical simulations of the cavitating propeller flow, the Schnerr-Sauer cavitation model based on a reduced Rayleigh-Plesset equation was used to model the sheet and tip vortex cavitation. An alternative Vorticity-based Adaptive Mesh Refinement (V-AMR) technique was employed for the accurate realisation of the TVC in the propeller's slipstream. In the hydroacoustic calculations, a porous Ffowcs Williams Hawkings equation (P-FWH) was employed together with the DES solver. The numerical hydrodynamic and hydroacoustic results are compared with those of experimental data for the benchmark propeller available from the University of Genova Cavitation Tunnel. The results show that both the RANS and DES solvers are successful for modelling of the sheet cavitation on the propeller blades. However, the prediction of the TVC extension using the RANS solver is found to be insufficient in comparison to the TVC prediction when using the DES method. This is due to the inherent modelling limitations of the RANS solver. In addition to hydrodynamic performance predictions, the overall noise spectrums were found in an agreement with the experimental data with discrepancies between the low and high-frequency region.

Application of Large Eddy Simulation to Predict Underwater Noise of Marine Propulsors. Part 2: Noise Generation

“…A very recent study, which was similar to the present investigation, compared the Newcastle round robin test case acoustic emissions for one operation point with the respective measurements from the University of Genoa (UNIGE) cavitation tunnel. The results obtained with DES and the Schnerr-Sauer cavitation model reached good agreement regarding the underwater noise signature between 100 Hz and 10 kHz [19].…”

Hydroacoustic analysis of a marine propeller using large-eddy simulation and acoustic analogy

“…It should also be noted that comparisons between experiments and computations on the noise from marine propellers were rarely reported in the literature (for a few exceptions see Bensow & Liefvendahl 2016, Ebrahimi, Seif & Nouri-Borujerdi 2019, Sezen et al. 2020, Sezen, Atlar & Fitzsimmons 2021 a , Kimmerl et al. 2021 and Lidtke et al.…”

“…In particular, the deviations across experiments were often above the values of 20 dB shown in figure 20. It should also be noted that comparisons between experiments and computations on the noise from marine propellers were rarely reported in the literature (for a few exceptions see Bensow & Liefvendahl 2016, Ebrahimi, Seif & Nouri-Borujerdi 2019, Sezen et al 2020, Sezen, Atlar & Fitzsimmons 2021a, Kimmerl et al 2021and Lidtke et al 2022, where also similar or more significant deviations were found). Therefore, the results in figure 20 compare well with similar studies in the literature and can serve as a useful reference to assess the performance of high-fidelity simulations in matching acoustic measurements.…”

Hydroacoustic and hydrodynamic investigation of bio-inspired leading-edge tubercles on marine-ducted thrusters

“…DES was used as opposed to RANS as it has been shown that the RANS solver does not capture the instabilities within the propeller wake flow [ 40 ], and in the case of tubercles, the suitability of the RANS solver has been questioned, especially in flow separation conditions [ 41 ]. In addition, it has been recommended to use high-fidelity solvers such as DES/LES when predicting the URN of marine propulsors [ 7 , 42 ]. The rotation rate was kept constant at 15rps and the advance velocity was varied to predict the open-water curve characteristics.…”