Numerical investigation of marine propeller underwater radiated noise using acoustic analogy Part 2: The influence of eddy viscosity turbulence models

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.…”

“…It is also recommended to remove the ‘end-caps’ from the permeable surface due to the wake structure crossing over the region, resulting in contamination of the noise signature, and this was done for this study [ 6 ]. In terms of permeable surface dimensions, the exact dimensions and location of the integral surface have not been defined clearly in the present literature, and it is still being investigated [ 7 ]. The permeable surface and the near-field receiver positions can be shown in figure 5 , and the location of the near-field receivers in terms of x, y and z is tabulated in table 2 .…”

“…The most popular acoustic analogy for hydroacoustics is the Ffowcs-Williams Hawkings (FW-H) method. Various studies have been conducted using different formulations of the FW-H acoustic analogy in both cavitating and non-cavitating flows [2][3][4][5][6][7]).…”

Physically plausible propeller noise prediction via recursive corrections leveraging prior knowledge and experimental data

“…1 In the maritime industry, heretofore, the impact of vessels on the environment was considered just in terms of atmospheric pollutant formation from the prime movers (Trivyza et al, 2021), release of toxic compounds from hull coatings (Torres and De-la Torre, 2021), or importation of exotic biological species through ballast water (Lakshmi et al, 2021) and biofouling (Song et al, 2020). Underwater Radiated Noise (URN) was just recently categorised as a form of pollution (Vakili et al, 2020a) due to the substantial increase of noise pollution on oceans worldwide (Sezen et al, 2021b). URN not only has severe effect on the marine ecosystem (Ferrier-Pagès et al, 2021;Di Franco et al, 2020) but also affects the crew and passenger comfort (Oldenburg et al, 2010).…”

“…-Computational Fluid Dynamics (CFD) based models (see Section 2.1.2) decouple the sound propagation from its source generation, allowing to separate the flow solution from the acoustic analysis (Sezen et al, 2021a). The viscous flow field, where the sound source is generated, is solved by means of a CFD method with an appropriate turbulence model and the sound propagation is treated by an integral method based on acoustic analogy (Sezen et al, 2021b). CFD-based models can be quite accurate and reliable at the expense of large computational requirements, which prevent their use at the design stage (Bosschers, 2018a).…”