Numerical Estimation of Underwater Radiated Noise of a Marine Propeller in Non-cavitating Regime
01 Jan 2019-pp 149-167
TL;DR: In this paper, the authors calculate the propeller noise in the non-cavitating regime for the uniform flow (no wake condition) with a commercial CFD software STAR-CCM+, while hydro-acoustic analysis is performed using Ffowcs Williams-Hawkings (FWH) equation.
Abstract: The underwater radiated noise levels (RNLs) emanating from surface and underwater marine platforms are becoming a topic of significant concern for all the nations in view of the global requirement to minimise the increasing adverse impact on marine life and maintain ecological balance in the so-called silent ocean environment. The studies have reported an increase in low-frequency ambient sea noise by an average rate of about 1/2 dB per year [Ross in IEEE J Ocean Eng 30(2):257–261, 2005 1] which is attributable to the growing fleet of ships. Marine propeller noise in both non-cavitating and cavitating regimes is an important component of the overall underwater radiated noise of a marine platform in addition to the machinery and flow noise. Merchant ships generally operate at low speeds, and hence, propeller noise in non-cavitating regime is an important area of concern. For military applications, design of low-noise propellers dictates the ships’ survivability and operational performance. Hence, design and development of low-noise propulsion systems and, in particular, low-noise propellers is a relevant topic of current focus which is in line with the global need of the hour to design eco-friendly ships. In this respect, the main scope of this study is to numerically calculate the propeller noise in the non-cavitating regime for the uniform flow (no wake condition). Flow around the propeller is solved with a commercial CFD software STAR-CCM+, while hydro-acoustic analysis is performed using Ffowcs Williams–Hawkings (FWH) equation. The numerical closure was achieved using k-e Reynolds-averaged Navier–Stokes (RANS) model. The predicted hydrodynamic performance curves and radiated noise levels have been validated from the published experimental and numerical results.
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TL;DR: This study reveals that metallic (NAB) propeller can be replaced by a composite propeller and the acoustic response from two-way FSI analysis will be more realistic due to the consideration of hydro-elastic effect of propeller.
6 citations
TL;DR: In this article , a two-way fluid-structure interaction (FSI) analysis is used to evaluate the hydrodynamic, hydro-elastic and acoustic response of a marine propeller.
5 citations
05 Oct 2020
TL;DR: In this paper, the effect of 2D non-uniform flow on the acoustic and hydrodynamic characteristics of a 2D propeller is presented. But, the reduction of non cavitating noise produced by the propeller would still remain a challenge.
Abstract: The impact of increased Underwater Radiated Noise (URN) over the past two decades on marine mammals has resulted in the pressing requirement to reduce it. Shipping contributes immensely to the URN. Propeller noise is a major source of URN. The reduction in Propeller noise can hence significantly help in the reduction of URN. With the sole objective of improving the hydrodynamic performance and ways to prevent cavitation are being employed in design propellers. However, the reduction of non cavitating noise produced by the propeller would still remain a challenge. In this present study, effect of 2D non-uniform flow on the acoustic and hydrodynamic characteristics is presented. The non-uniformity in the flow is generated by placing a flat plate in front of the propeller. The SPL has been calculated by using the two-step Ffowcs William and Hawkings (FW-H) equations from the pressure distribution at various points around the propeller. SPL at various points in the downstream and propeller disk plane are numerically predicted and discussed.
01 Sep 2019
TL;DR: Soydan et al. as mentioned in this paper investigated the hydro-acoustic performance of the DTMB 4119 model propeller with varying diameters, revolutions, blade number under in open water at noncavitating conditions.
Abstract: The propeller is the most dominant source of noise generated by ships and submarines. Research of underwater noise of the marine propellers has a great interest in recent years. In this study, the hydro-acoustic performance of DTMB 4119 model propeller has been investigated with varies diameters, revolutions, blade number under in open water at noncavitating conditions. Flow around the propeller has been solved computational fluid dynamics method using unsteady Reynolds Averaged Navier Stokes (uRANS). Hydro-acoustic analysis have been performed using unsteady RANS with Ffowcs-Williams and Hawkings (FW-H) equation. Propellers Sound Pressure Level (SPL) values also have been carried out with semiempirical Brown Formula and then Overall Sound Pressure Level (OASPL) values have been calculated. Finally, OASPL formulas have been developed and results have been compared. INTRODUCTION Traditionally, only engineers and designers of submarines, naval fishing and research vessels have had a significance interest in underwater radiated noise. In recent years, however, underwater noise has become a growing concern throughout the entire maritime industry. Sources of underwater radiated noise on a marine vessel can be divided into three main categories; engine, flow noise and propeller noise [Carlton, 2012]. To reduce the engine noise, isolation equipment can be installed, or the engine foundation may be resiliently mounted instead of rigidly mounted. Ship hull form should also be designed to decrease the hydrodynamic noise. But it is the propeller that is the dominant noise source on marine vessels. 1 Ph.D. student in Faculty of Naval Architecture and Ocean Engineering, Email: ahmetsoydann@gmail.com 2 Assoc. Prof. in Faculty of Engineering, Email: baha.zafer@istanbul.edu.tr 3 Prof. in Faculty of Naval Architecture and Ocean Engineering, Email: sbal@itu.edu.tr AIAC-2019-068 Soydan, Zafer & Bal 2 Ankara International Aerospace Conference Propeller noise is important for detection of vessel location and velocity, but also impacts the comfort of passengers and the environment. Due to these reasons, hydrodynamic properties and acoustic performance should be taken into consideration when designing propellers. Therefore, an accurate calculation of the noise due to marine propellers is an important subject within the maritime industry. The designer should consider that the propeller must satisfy the desired thrust and torque values, while minimizing the radiated noise in the concept design stage. One of the most important studies that formed the basis of today's acoustic studies was carried out by [Lighthill,1952]. Based on Lighthill's work, [Curle, 1955] conducted a study about body and fluid interaction. In 1969, a method developed by Ffowcs-Williams and Hawkings (FW-H) for calculation of noise of an arbitrary body moving in a fluid became one of the milestones of acoustic studies [Ffowcs Williams and Hawkings, 1969]. With the development of computer technology and numerical methods, FW-H method became available also hydro-acoustic predictions. [Seol, Suh and Lee, 2002] investigated the non-cavitating underwater propeller noise using time-domain acoustic analogy (FW-H equation) and boundary element method. [Seol, Suh and Lee, 2005] extended their work to calculation of blade sheet cavitation noises of the underwater propeller. The flow field was analyzed with potential-based panel method, and the time-dependent pressure and sheet cavity volume data were used as the input for FWH formulation to predict the far-field acoustics. [Salvatore and Ianniello, 2003] published the preliminary results for cavitating propeller noise predictions. [Ozden, Gürkan, Ozden, Canyurt and Korkut, 2016] investigated numerically the INSEAN E1619 submarine propeller in open water, behind a generic DARPA suboff submarine and within imposed wake cases at non-cavitating condition. [Purwana, Ariana, Wardhana and Handani, 2017] used to numerical simulation to predict hydrodynamic performance and noise around non cavitation propellers. The performance of propeller was predicted by MRF technique (Multiple Reference Frame). The 3D model propeller of B-series propeller was simulated with various advance coefficients. [Tewari, Misra and Vijayakumar, 2019] also investigated the underwater radiated noise levels of DTMB 4119 model propeller by a 3D numerical simulation of the flow around propeller operating in non-cavitating regime for the uniform flow (no wake) condition with different advanced coefficients. The influence of skew and rake angles on noise and hydrodynamic performance of propeller is very crucial. [Gorji, Ghassemi and Mohamadi, 2017] conducted a numerical simulation of the acoustic pressure generated by a marine propeller (DTMB 4119) in different skew and rake angles. Lin 1996, into quantifying propeller noise inboard a twin-screw passenger vessel took a practical approach [Raestad, 1996]. Full scale experiments were conducted on 15 cruise liners and ferries. According to this study, noise caused by tip vortices can be estimated by tip vortex index (TVI) technique. Later this TVI technique, coupling an empirical formula with a lifting surface method, was applied for the prediction of the inboard noise level of a three bladed DTMB 4119 model propeller [Sezen, Dogrul and Bal, 2017]. Two and three-bladed model propellers were investigated for the hydro-acoustic performance operating under cavitating and non-cavitating conditions. In this study, underwater propeller noise of DTMB 4119 propeller is investigated under different conditions by a 3D numerical simulation and Brown formula. Also, a very practical and simple method, based on the semi-empirical Brown formula is described for non-cavitating marine propellers. GOVERNING EQUATIONS The governing equations are the continuity and the uRANS (Unsteady Reynolds Averaged Navier-Stokes) equations for the time dependent, three-dimensional, incompressible flow [Versteeg and Malalasekera, 2007]; AIAC-2019-068 Soydan, Zafer & Bal 3 Ankara International Aerospace Conference ( ) 0 i i t x + = (1) is the continuity, ( ) ( ) 2 ( ' ') 3 i j j i i l ij i j j i j j i l j u u u u u P u u t x x x x x x x + = + + − + − (2) is the momentum equations where i x and i expresses the tensor form of axial coordinates and velocities, respectively, ij is Kronecker Delta, is the density , is the kinematic viscosity of the fluid and ' ' i j u u − are the unknown Reynolds stresses.. The well-known SST k-ω turbulence model is used to simulate the turbulent flows. Further details for the SST kω turbulence model can be found in [Wilcox, 2006]. For the acoustic analysis of the propeller the integral equation FW-H (Equation 3) is solved to find the far-field sound of the propeller [Ffowcs Williams and Hawkings, 1969]. 2 2 2 2 2 0 1 { ( )} {[ ( )] ( )} ij ij ij i n n i j p p T H f P n u u f a t x x t t − = − + − + (3) 0 {[ ( )] ( )} n n n u f + − Where p , is the far field sound pressure ( 0 p p p = − ) , ij T is the Lighthill tensor and 0 a is the sound velocity in the far field. The terms at RHS are defined as quadruple, dipole and monopole source, respectively. Also ( ) f and ( ) H f are the Dirac delta function and the Heaviside function, respectively. NUMERICAL MODELLING Geometry and Boundary Conditions DTMB 4119 propeller has 3 blades and no skew and no rake with diameter 0.3048 meters. DTMB 4119 propeller, as given below in Table 1, are designed with NACA 66 modified profile and a=0.8 camber line. 3-D model of the propeller is shown in Figure 1. Table 1. DTMB 4119 propeller geometry [Brizzolara, Villa and Gaggero, 2008] r/R c/D P/D tmax/c fmax/c 0.20 0.3200 1.1050 0.2055 0.0143 0.30 0.3635 1.1022 0.1553 0.0232 0.40 0.4048 1.0983 0.1180 0.0230 0.50 0.4392 1.0932 0.0902 0.0218 0.60 0.4610 1.0879 0.0696 0.0207 0.70 0.4622 1.0839 0.0542 0.0200 0.80 0.4347 1.0811 0.0421 0.0197 0.90 0.3613 1.0785 0.0332 0.0182 0.95 0.2775 1.0770 0.0323 0.0163 0.98 0.2045 1.0761 0.0321 0.0145 1.00 0.0800 1.0750 0.0316 0.0118 AIAC-2019-068 Soydan, Zafer & Bal 4 Ankara International Aerospace Conference Figure 1: DTMB 4119 propeller geometry Figure 2 shows the computational domains and boundary conditions with propeller in the rotational domain. The right and left sides of the computational domain have been defined as the velocity inlet and pressure outlet, respectively. The propeller has been defined as no slip wall to impose the kinematic boundary condition. The upper surface has been defined as symmetry plane. The computational domain consists of unstructured tetrahedral elements. Figure 3 shows the unstructured tetrahedral mesh generated around the propeller. Figure 2: Computational domain and boundary condition for validation and verification case Verification and Validation In the first place, verification and validation study has been carried out. Flow around DTMB4119 propeller has been solved with uRANS. SST k-ω turbulence model has been used. Second order-upwind scheme has been selected for the momentum and turbulence terms and the simple algorithm for velocity pressure interaction has been selected. Time step size has AIAC-2019-068 Soydan, Zafer & Bal 5 Ankara International Aerospace Conference been chosen as the time required for a 0.1° of reference frame rotation of the propeller [Ozden, Gürkan, Ozden, Canyurt and Korkut, 2016]. Three different mesh have been generated for verification and validation study. Uncertainty analysis has been applied with Grid Convergence Index (GCI) as recommended by ITTC for CFD verification [ITTC, 2011]. Grid length refinement has been selected greater than 1.3 as recommended in (Celik, Ghia, Roache, 2008] and [Roache, 1998]. The number of elements are given below in Table 2. Table 2. Number of grids. Grid Type Number of Elements Course 650,981 Medium 946,006 Fine 1,389,509
References
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TL;DR: In this paper, the authors present the trends in world merchant shipping, including important changes in propulsion plants as well as in numbers and sizes of ships, and the need for radiated noise measurements of these new ship types will be stressed.
Abstract: The rapid increase in world shipping results in an increase in low-frequency ambient noise at an average rate of about 1/2 dB per year. During the past 10 years there has been a virtual revolution in the sizes and speeds of merchant ships, resulting in significant increases in the noise radiated by the average ship. This trend is continuing. In this paper, the trends in world merchant shipping will be presented, including important changes in propulsion plants as well as in numbers and sizes of ships. The need for radiated noise measurements of these new ship types will be stressed. Ambient noise is also dependent on the geographical distribution of shipping. The LRAPP-sponsored program to establish standard shipping distributions for the Northern Hemisphere will be discussed, and the reliability of current information will be assessed.
152 citations
TL;DR: In this article, a numerical study on the non-cavitating and blade sheet cavitation noises of the underwater propeller is presented, where the noise is predicted using time-domain acoustic analogy.
100 citations
TL;DR: In this paper, a scattering approach is applied in which the acoustic pressure field is split into the known incident component and the unknown scattered component, and the effect of sound deflection and scattering effect on the duct is considered with the BEM.
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TL;DR: In this article, the authors used a CFD-based URANS hydrodynamic prediction approach, coupled with the Ffowcs-Williams Hawkings (FWH) equation for noise propagation.
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TL;DR: In this article, a hydrodynamic model for transient sheet cavitation on propellers in non-uniform inviscid flow is coupled with a hydroacoustic model based on the Ffowcs Williams-Hawkings equation.
Abstract: The numerical prediction of the acoustic pressure field induced by cavitating marine propellers is addressed. A hydrodynamic model for transient sheet cavitation on propellers in non–uniform inviscid flow is coupled with a hydroacoustic model based on the Ffowcs Williams–Hawkings equation. The proposed hydroacoustic approach, novel to marine applications, allows to split the noise signature into thickness and loading term contributions. Both hydrodynamic and hydroacoustic model equations are solved via boundary integral formulations. Numerical predictions of the propeller noise by using the Ffowcs Williams–Hawkings equation are compared to those obtained by a classical Bernoulli equation approach. The influence of cavitation on the noise waveforms is discussed by comparing non–cavitating and cavitating propeller flow results.
39 citations