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

Abstract

Methods to predict underwater acoustics are gaining increased significance, as the propulsion industry is required to confirm noise spectrum limits, for instance in compliance with classification society rules. Propeller–ship interaction is a main contributing factor to the underwater noise emissions by a vessel, demanding improved methods for both hydrodynamic and high-quality noise prediction. Implicit large eddy simulation applying volume-of-fluid phase modeling with the Schnerr-Sauer cavitation model is confirmed to be a capable tool for propeller cavitation simulation in part 1. In this part, the near field sound pressure of the hydrodynamic solution of the finite volume method is examined. The sound level spectra for free-running propeller test cases and pressure pulses on the hull for propellers under behind ship conditions are compared with the experimental measurements. For a propeller-free running case with priory mesh refinement in regions of high vorticity to improve the tip vortex cavity representation, good agreement is reached with respect to the spectral signature. For behind ship cases without additional refinements, partial agreement was achieved for the incompressible hull pressure fluctuations. Thus, meshing strategies require improvements for this approach to be widely applicable in an industrial environment, especially for non-uniform propeller inflow.

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

“…2020, Sezen, Atlar & Fitzsimmons 2021 a , Kimmerl et al. 2021 and Lidtke et al. 2022, where also similar or more significant deviations were found).…”

“…However, in the same works they acknowledged that RANS is inherently not well suited to reproduce the dynamics of the vortices populating the propeller wake and their instability, which were expected to become the major source of noise at a short distance from the propeller through the quadrupole terms of FWH. This conclusion was confirmed in later studies (Lidtke, Humphrey & Turnock 2016;Sezen & Kinaci 2019;Sezen et al 2021b), urging the need for more accurate techniques, as detached-eddy simulation (DES) or large-eddy simulation (LES), in order to be able to capture properly the propeller wake, cavitation phenomena and their contribution to noise from marine propulsion. To verify the latter point, Cianferra, Ianniello & Armenio (2019a) conducted LES on a canonical case, represented by a square cylinder of finite spanwise extent, immersed in a uniform flow.…”

“…(2021 b , 2022) proposed a fix to this problem. The porous approach was recently pursued by Stark & Shi (2021) and Kimmerl, Mertes & Abdel-Maksoud (2021). In particular, Stark & Shi (2021) analysed the acoustic signature of four-bladed ducted thrusters, using data from improved delayed detached-eddy simulation (IDDES), conducted on an unstructured hexahedral mesh consisting of about 13 million elements.…”

“…Implicit LES on grids composed of volumes was utilised by Kimmerl et al. (2021) to study the Newcastle propeller and the P1595 test case.…”

Investigation into the Hydrodynamic Noise Characteristics of Electric Ducted Propeller

“…It is also an important energy consumption equipment and a noise source for UUV in reconnaissance, intelligence collection and ocean exploration [3]. Since the motor and controller can be placed into the cabin, hydrodynamic noise is the main source of the ducted propeller [4]. Therefore, in-depth study on the acoustic characteristics of the ducted propeller under different working conditions is of great significance to put forward effective noise reduction measures and improve the operation ability of UUV.…”