Numerical simulation of the cavitating noise of contra-rotating propellers based on detached eddy simulation and the Ffowcs Williams–Hawkings acoustics equation

Abstract

Contra-rotating propellers (CRPs) are widely used in different kinds of underwater vessels, owing to their excellent stability, propulsive efficiency, and balanced torque distribution characteristics. However, the cavitation that occurs due to their high rotational speeds also generates high levels of cavitation noise. In this study, CRP noise radiations were predicted via detached-eddy simulations with the shear stress transfer k-ω turbulence model, the Ffowcs Williams–Hawkings (FW–H) acoustics model, and the Schnerr–Sauer cavitation model. The cavitation noise of the CRP was predicted using sound radiation theory for spherical bubbles and compared to non-cavitation noise levels from the FW–H equation. It was found that the non-cavitation noise of the CRP is significantly louder in the axial direction than in the radial direction. Furthermore, the noise sound-pressure levels (SPLs) of the flow field generally decrease with increasing frequency. When the effects of cavitation on the flow are taken into account, the SPLs of the CRP noise become significantly higher at all equidistant positions from the center of the propeller. The anisotropy in sound pressure also becomes insignificant when cavitation is present.

A Delayed Detached Eddy Simulation Model for the Simulation of Complex Turbulent Flow

“…9 that there is a zone near the pressure side where the average velocity has a slope approximately twice the rotation rate of the system. Compared with the direct numerical simulation (DNS) results (Durbin 1991;Zhang et al 2021), the difference between the DDES_NL model and the direct numerical simulation results was found to be small. The important finding is that the URANS method cannot capture the flow characteristics of asymmetric velocity distribution due to rotation in the channel, however, both DDES_NL models can capture such asymmetric flow characteristics.…”

“…The numerically calculated head and efficiency are by the experimental data over the whole operating range (Zhang et al 2021), which has been done at the experimental base of the 704th Research Institute of China Shipbuilding Industry Corporation and can reflect the hydraulic performance of the centrifugal pump. Therefore, the use of the DDES_NL method to predict the hydraulic performance of the centrifugal pump is feasible.…”

“…    in the streamwise (x axis), wall-normal (y axis), and spanwise (z axis) directions, respectively, with the120 120 60  grid nodes (Zhang et al 2021).…”

Interaction between the helical vortices shed by contra-rotating propellers

“…DES was also exploited by Hu et al 31 to reconstruct the acoustic emission from contra-rotating propellers, by coupling this methodology with the Ffowcs-Williams and Hawkings acoustic analogy on a computational mesh consisting of about 7 Â 10 6 cells. However, this study was mainly focused on the prediction of the noise originating from cavitation phenomena over the blades of the propellers, while no details were reported on the wake features and, in particular, on the dynamics of their tip vortices.…”

Influence of Stern Rudder Type on Flow Noise of Underwater Vehicles

“…SEZEN S et al used RANS and Detached-Eddy Simulation (DES) solvers, combined with the porous FW-H (P-FWH) equation, to predict the hydrodynamic and underwater acoustic performance of a marine propeller in open water [17]. HU J et al predicted contra-rotating propeller noise using the shear stresstransfer k-ω turbulence model, FW-H acoustic model, and the Schnerr-Sauer cavitation model [18]. Kolahan et al used the LES turbulence approach and Sauer mass transfer models to analyze the cavitation phenomenon around the sphere in different cavitation numbers [19].…”