V.Rama Krishna ,Srinivas Prasad Sanaka ,N.Pardhasaradhi ,B.Raghava Rao

a Naval Science & Technological Laboratory,Visakhapatnam,532007,India

b Department of Mechanical Engineering,V.R.Siddhartha Engineering College,Vijayawada,520 0 07,India

Keywords:Advance ratio Coupled analysis CFD Marine propeller Hydrodynamic parameters Two-way fluid structure interaction

ABSTRACT Marine propellers have complex geometry and their performance is determined by costly and time consuming open water experiments.Use of numerical techniques helps researchers in effective design of propellers.Several approaches are used that predicted either hydrodynamic and acoustic response or structural response.Two-way fluid-structure interaction (FSI) analysis is a very useful approach providing all three responses which helps in the design,analysis and optimization of a propeller.The objective of this paper is to predict the hydro-elastic response of a propeller using two-way FSI on a 0.2m diameter,DTMB-4119 propeller using ANSYS software.Two-way FSI analysis is carried out using system coupling approach that transfers the data between the structural and fluid solvers.The turbulence effects are captured using the large-eddy simulation (LES) model and the Ffowcs Williams Hawkings (FWH) acoustic model is used for evaluating the sound pressure level (SPL) generated by propeller.Analysis is extended to evaluate the hydro-elastic and acoustic response of the propeller after validating the hydrodynamic performance with the experimental result in the literature.The results from Two-way FSI analysis are in close agreement when compared with the one-way FSI analysis.Two-way FSI can accommodate the peak value of stress and deformation developed during the initial part of the transient solution which is important in the design of propeller.This study reveals that metallic (NAB) propeller can be replaced by a composite propeller.The acoustic response from two-way FSI analysis will be more realistic due to the consideration of hydro-elastic effect of propeller.

1.Introduction

Marine propeller converts mechanical power to thrust power to propel the ship in a forward direction through the water.Hydrodynamic load acts on the blade of the propeller during its rotation.The propeller blades are deformed and stresses are induced due to the hydrodynamic loads.Computation of hydrodynamic performance parameters and the structural response of propeller are very much important from the design point of view.Stuart Dodge Jessup [1]carried an experimental investigation on a DTMB 4119 Propeller of 0.3m diameter with three blades and estimated the hydrodynamic coefficients of the propeller.Y.L.Young [2,3]used a coupled boundary element and finite element approach and FSI studies are carried out on DTMB 4148 and DTMB 4383 Propellers,PROPCAV and ABAQUS packages were used for modal analysis of propeller.FSI studies are also carried out on flexible composite propellers 5471 and 5479 and predicted the hydrodynamic and inertial loads.Hannes Schmucker et al.[4]presented the FSI results of an axial hydraulic turbine.ANSYS-CFX is used for fluid flow analysis and ANSYS classic is used for structural analysis.Coupling between both the solvers are established.The deflections and stresses are computed on the turbine blade.Robert L.Campbell[5]explored the use of FSI for turbo-machinery applications and analyzed the results of FSI on NACA 66 fin and also on impeller pump.Friedrich-Karl Benra et al [6]simulated the fluid structure interaction problem by considering the external flow over a square cylinder with a thin plate at the trailing edge.External flow velocity varied from 0.27 to 0.64 m/s and deformation with time has been plotted for one-way and two-way coupling methods.At higher velocities,the two-way FSI characteristics are different from the one-way FSI method.It was concluded that the two-way FSI results were close to reality.Mosaad,M.A.et al.[7]carried out computational analysis using FLUENT and studied the effect of skew angle on DTMB-P4119 propeller to select the best angle and to minimize the induced vibrations.Hai-tao et al.[8]carried out one-way fluid-structure interaction on a 3.6 m diameter DTMB 4119 propeller at a rotational velocity of 185 rpm and predicted the hydrodynamic loads using Boundary Element Method (BEM) on the rigid blade of propeller and then the hydrodynamic pressures are applied as external normal surface traction for the finite element analysis and determined the total deformation and stresses for the designed condition and also concluded that additional work to be carried out to predict the hydrodynamic load induced due to structural response.Syed-badshaw Khalid et al.[9]faced challenges to simulate two-way FSI analysis using Ansys workbench on a 4 m diameter,four-bladed vertical tidal turbine.Kiam Beng Yeo et al.[10]simulated fluid flow first and then these unidirectional results are exported to structural solver in SOLIDWORKS software.Calculations were done on a 0.25 m diameter,3 blade propeller with steel material.Maximum stress was observed near the hub and is decreased towards the tip of propeller.Hyoungsuk Lee et al.[11]developed a numerical methodology for predicting the hydro-elastic behavior of flexible marine propellers.Boundary element method code,KPA14 was used to calculate the hydrodynamic loads on the propeller.A Finite Element analysis solver ABAQUS is used to predict the deformation.The results on P5479 and P5475 propellers were validated.Sangho Han et al.[12]conducted FSI analysis on a 9.86 m diameter,KP458 propeller using STR-CCM+and ABAQUS.They validated the computed hydrodynamic performance results of P5479 propeller and observed that the efficiency values are lower than the experimental data,especially at higher advance ratio values.The differences between rigid propeller and flexible propeller results are observed.R.K.B.Gallegos and R.N.Sharma [13]carried out two-dimensional fluid-structure interaction of external flow at 1 m/s velocity on a flexible plate located behind a cylinder.The oscillation amplitude and frequency of the plate tip were studied at different diameters of the cylinder.Boumediene.K and Belhenniche.S.E [14]carried out numerical analysis of turbulent flow on a DTMB 4119 marine propeller of 0.3048 m diameter by using RANS in FLUENT software and predicted hydrodynamic performance of the propeller.Jitendra Kumar [15]carried out bi-directional FSI analysis on tidal turbine blade.Coupling between fluid flow solver and structural solver is formed to create data transfers at the end of the each iteration.Dynamic mesh settings were used to control the solution.Ehsan Yari and Hassan Ghassemi [16]performed the simulations to compute the hydrodynamic parameters using boundary element method on a SPP-841 propeller at a velocity of 3.13 m/s and in the advance ratio from 0.4 to 1.3.Computed parameters are validated and found that the efficiency values are slightly deviated.

Vesa Niemiinen [17]performed FSI simulation on P1374 propeller at J=0.49 and at 7 rps.The solution was converged in 6 coupling steps.Steady state simulations are carried out in FLUENT software.ABAQUS software was used for structural analysis.Non-conformal mesh is used at the fluid solid interface and it was concluded that the Fluid structure interaction analysis can be carried out for several other operating points.Abhishek Kumar Tewari et al.[18]numerically calculated the propeller noise in the non-cavitating regime on a DTMB 4119 propeller.Flow around the propeller is solved with STAR-CCM+,while hydro-acoustic analysis is performed using Ffowcs Williams-Hawkings (FW-H) equation.Takuya Suzuki et al.[19]developed a two-way FSI procedure by combining blade element momentum theory and finite element method to study the 9m diameter ocean current turbine blade.Deformation of the blade was computed in the velocity range of 0.5 to 5.0 m/s.Jiasheng Li et al.[20]developed a numerical model for predicting the hydro-elastic behavior of marine propellers.Panel method was coupled with finite element method and Modal analysis is carried out on 4119,4381 and 4382 propellers.Maljaars Pieter et al.[21]used coupling between BEM and FEM for analyzing the hydro-elastic behavior of composite propellers and validated the results obtained from the FSI.Uncertainties were found at higher advanced ratio values.Boumediene.K and Belhenniche.S.E [22]computed the force and moments on Seiun Maru highly skewed marine propeller using ANSYS FLUENT 14.0 and evaluated open water performance in terms of thrust and torque coefficients for an advance ratio of 0.1 to 1.0 and validated the results.S.Rama Krishna et al.[23]performed a one-way fluidstructure interaction analysis on a 5 bladed 0.2 m diameter propeller at a rotational speed of 780 rpm.Pressure loads are computed from FLUENT and are exported to Abacus to compute the deformation and strength of the propeller.Abouzar Ebrahimi et al.[24]computed the hydrodynamic parameters on a 0.2 m diameter DTMB 4119 propeller and the acoustic effects are studied using panel method.Habib Ullah et al.[25]carried out one-way fluid structure interaction on three bladed tidal current turbines.The diameter of the turbine is 0.5 m and rotational speed of the rotor is 191 rpm.ANSYS-CFX is used for fluid flow analysis and hydrodynamic loads are transferred as input to the static structural analysis.Goutam Kumar Saha et al.[26]studied the hydrodynamic performance of four bladed,1.6 m diameter,B-series marine propeller using CFD simulations and validated the methodology and observed that thrust coefficient (K T) and torque coefficient (KQ)decrease with the increase in the advance ratio (J).The efficiency trend is nonlinear and increases to a maximum value before decreasing drastically with increasing J value.At higher J values,the efficiency is deviated from empirical values.Hai-peng Guo et al.[27]predicted hydrodynamic characteristics of a marine propeller using the CFD method.Analysis is carried out on two propellers,ONRT propeller and DTMB 5415 propeller.It was observed that the efficiency of DTMB 5415 propeller is deviating from the experimental data in the range of the advance ratio from 0.6 to 1.Fatima Bouregba et al.[28]carried out hydrodynamic analysis on Wageningen B series 4,5,6 bladed propellers using ANSYS-FLUENT.Six bladed propeller was recommended for open water flows.Mujahid Badshah et al.[29]compared the results obtained from computational fluid dynamics and fluid-structure interaction models for the performance prediction of tidal current turbines and concluded that for small deformations there is no much variation in hydrodynamic performance,but for large deformation conditions the variation in performance is considerable.Kai Yu et al.[30]carried out a one-way fluid-structure interaction analysis on a DTMB 4119 Propeller of 0.3048 m diameter using ANSYS Workbench and hydrodynamic loads are computed using FLUENT.The total deformation and maximum stresses are plotted at different advance ratios.The maximum equivalent stress is near the hub on the blade.?ukasz Marzec et al.[31]applied two-way FSI method for a vertical axis wind turbine.Ansys software is used for all numerical simulations.All Couplings between unsteady Reynolds Averaged Navier-Stokes Equations with unsteady linear elasticity equations are used in FSI approach.It was concluded that the deformation of the turbine rotor causes an increase in turbine performance.

Fig.1.DTMB Propeller 0.2m diameter.

One-way fluid-structure interaction studies are carried out by the early researchers did not predict the actual response of the propeller.The actual response demands two-way fluid-structure interactions between fluid and solid.The literature available on two-way FSI approach for marine propellers is limited.The twoway FSI approach is more realistic as identified from the existing literature.The data transfers in two-way system coupling up to only 100 iterations are observed in the literature.Researchers carried out FSI analysis only at one advance ratio value.Yet,there is a need for a systematic study.Two-way FSI analysis on the marine propeller is challenging and sensitive due to the complex propeller geometry,transient analysis,propeller rotational effects,coupling between the fluid and solid,convergence issues and need powerful computational facilities.Also,the transient acoustic data presented by the researchers on marine propeller is limited.A comparative study of hydrodynamic performance characteristics is not available for one-way and two-way FSI approaches along with experimental data.In this paper,an attempt is made to adopt two-way FSI analysis for predicting the hydrodynamic performance,structural response and acoustic signature for different advance ratios and use of different materials.

2.Geometry and discretized model

2.1.Propeller geometry

Three bladed DTMB 4119 propeller with 0.2 m diameter is created using ANSYS Workbench and is shown in Fig.1.NACA 66 modified (a=0.8) profile is used for the blade sections.The propeller selected is used for both validation [24]and also for the hydro-elastic computational analysis.The propeller geometrical details are given in Table 1.

Table 1 Propeller geometry parameters.

Fig.2.Fluid domain considered for external flow.

Fig.3.Discretized rotating fluid domain.

2.2.Discretized solid and fluid domains

The entire computational fluid region is divided into two domains.One is a stationary cylindrical domain and the other is a rotational cylindrical domain that surrounds the propeller.The overall fluid domain dimensions are shown in Fig.2.The diameter of the stationary fluid domain is 8D and the location of inlet boundary is at a distance of 3D from the propeller and the exit boundary is 4D from the propeller.Two separate grids are generated using ICEM CFD for stationary and rotating fluid domains.Tetrahedral cells are used in all fluid and solid domains in this analysis due to the complexity of propeller geometry.The Discretized domain around the propeller in a moving reference frame is illustrated in Fig.3.A smaller cell size is used at the tip of the propeller.The grid on the propeller is shown in Fig.4.Tetrahedral mesh is generated in the cylindrical stationary fluid domain and is shown in Fig.5.The total number of elements used in the fluid domain for transient fluid flow analysis is 1.44 Million.Both the propeller blade and hub domains are discretized using tetrahedral cells and the number of cells used for the transient structural analysis is 0.45 Million.

Fig.4.Mesh on Propeller.

3.Two-way fluid structure interaction analysis

3.1.Transient fluid flow analysis

The time step is determined based on the sampling frequency of the sound field.According to Nyquist’s law of sampling,the highest frequency of sound field that can be restored is half of the sampling frequency.In this study,the time step used is 0.0005 second and is estimated using Eq.(1) in order to accommodate a maximum frequency of 1000 Hz.

The turbulence flow model used is large eddy simulation (LES)and Ffowcs Williams Hawkings (FWH) acoustic model is used to capture acoustic effects.The density of water considered is 998.2 kg/m3and dynamic viscosity is 0.0 010 03 kg/m-s.The propeller rotational speed is selected as 792 rpm and therefore the fluid around the propeller is rotated with this speed so as to use the moving reference frame (MRF) approach.The interface between the stationary fluid domain and the rotating fluid domain is defined as ‘interior’.The velocity boundary condition is used to define the advanced velocity at the inlet to the fluid domain.Pressure outlet is the boundary condition imposed and zero pressure is defined at the outlet.External surfaces of propeller are defined as wall type and used as source for acoustic analysis.Reference acoustic pressure used for acoustic analysis is 1e-6 Pascal.

3.2.Transient structural analysis

Nickel Aluminum Bronze (NAB) material is used for the marine propeller due to its high corrosion resistance and high yield strength.The density of NAB material is 7556 kg/m3,Young’s Modulus is 121 GPa and the Poisson’s ratio is 0.34.Hub inner surface is used as fixed support and propeller blades,hub outer surfaces are used as a fluid-solid interface.

3.3.Analysis settings for FSI coupling

A fluid-solid interface boundary condition is applied on all faces of the propeller exposed to fluid.The ANSYS workbench is used to couple FEA and CFD analyses through the system coupling component.The ANSYS system coupling is used to couple CFD solver FLUENT with the transient structural solver to set up a transient coupled fluid structure interaction simulation.The total simulated time is 0.6s for one-way and two-way coupled simulations.The time step used is 0.0005s in fluid flow simulation,transient structural analysis and in coupled analysis.Two data transfers are set up to transfer the force data from CFD to FEA solver and displacement data from FEA to CFD solver.The contributing region for the data transfer is fluid-solid interface.This two-way data transfer is accomplished by enabling the ‘smoothing’ and ‘re-meshing’ in dynamic mesh settings of the software.To improve the element quality by moving locations of nodes with respect to surrounding nodes,smoothing method is used and the diffusion parameter selected as 1.5.Re-meshing is used to relocate and adjust the grid with minimum and maximum length scales.Maximum cell skewness used is 0.9 to ascertain the quality of the grid.Use of proper dynamic mesh methods and settings in two-way FSI analysis of is more important to resolve the convergence issues commonly raised during iterative solution.

4.Results and discussion

4.1.Hydrodynamic performance of propeller

Thrust and moment values are directly computed from fluid flow analysis.Thrust coefficient,moment coefficient and efficiency are then calculated using Eqs.(2),(3) and (4) respectively for various operating conditions in this study.

The hydrodynamic performance of the propeller is evaluated by varying the advance ratio,J from 0.5 to 1.0 for a fixed propeller diameter of 0.2 m and at a rotational speed of 792 rpm.Rigid propeller simulations are carried out in one-way FSI by ignoring the hydro elastic behavior of propeller.Two-way FSI simulations are performed with two-way data transfer to predict the hydrodynamic performance of DTMB 4119 Propeller and its structural response.These results along with experimental data [24]are plotted in Fig.6.A close agreement is observed for thrust and torque coefficients (KT,KQ) with experimental data by both the methods.However,the efficiency of the propeller depends on the thrust coefficient,torque coefficient and advanced ratio.The efficiency computed from two-way FSI analysis is close to the experimental data than the one-way coupled FSI analysis.The variation is very low for the advanced ratios below 0.7 and the variation increases beyond 0.7.Hence,it can be concluded that one-way FSI can be used for the accurate prediction of hydrodynamic performance for lower advance ratios up to 0.7 whereas two-way FSI analysis is needed for higher advanced ratios.Since the hydrodynamic load on the propeller at higher advanced ratios is high and to capture the realistic behavior,it is recommended to use two-way coupling due to the larger interaction parameters between solid and fluid.A similar trend has been observed [9]in the performance of the vertical axis tidal turbine.The propeller chosen [1]is designed for an advance ratio of 0.833.Therefore,the efficiency of the propeller is lower at low advance ratio values and the decreasing trend started at higher advance ratio values.The results presented in this plot clearly indicate that the propeller performance is poor at off design conditions as expected.

Fig.5.Fluid domain and mesh.

Fig.6.Comparison of One-way FSI,Two-way FSI Results with experimental data.

4.2.Structural response of propeller

4.2.1.Metallicpropeller

The propeller blades are deformed due to the action of hydrodynamic loading.The propeller is assumed to be made of a homogeneous,isotropic,and linear elastic material in the analysis for metallic propeller.The structural response of the propeller has been plotted in terms of total deformation and equivalent von-Mises stress.The variation of these parameters is illustrated in Figs.7 and 8 for an advance ratio ranging from 0.5 to 1.0.These plots indicate that the magnitude of maximum von-Mises stress and total deformation decrease with the increase in advance ratio from 0.5 to 1.As the advance ratio increases,the hydrodynamic loads on the propeller decrease and therefore the stresses induced and the total deformation decreases.Similar trend has been observed in the earlier work [30].Marginal variation is observed between the one-way and two-way fluid structure coupling for total deformation due to the smaller diameter of the propeller and the higher yield strength of the NAB material.However,increased stresses are observed in the two-way FSI analysis,and this is observed at all advanced ratios considered in the analysis.This indicates the necessity of using the two-way FSI for accurate prediction of the structural performance of the propeller.For larger diameter,lightweight and flexible propellers this variation can be predominant demanding the two-way FSI analysis.Unlike in hydrodynamic performance,where two-way FSI is advantageous at higher advanced ratios,two-way FSI is required at lower as well as at higher advanced ratios for evaluation of structural performance.The computed stress and deformation are plotted with simulation time up to 0.015 second at 0.833 advance ratio in Figs.9 and 10.The stress and deformation values at the initial stages of transient simulation are higher in two-way fluid-structure interaction than one-way FSI analysis.Two-way FSI analysis is successfully carried out on the selected propeller using NAB material.For larger diameter propeller,flexible materials such as fiber-reinforced composites,the similar analysis may create the divergence issues to carryout two-way FSI analysis because of the higher loads act on propeller at the initial stages of transient stimulation as observed in these plots.The variation of maximum total deformation with time up to 0.6 s is illustrated in Fig.11,for one-way and two-way approaches at J=0.833.The contours of total deformation and von-Mises stress at different advance ratio by using two-way FSI are shown in Fig.12.The deformation and von-Mises stress magnitude are high at J=0.5.The location of maximum stress is at the root of the blade and the location of maximum deformation is at the tip.The contours of the blade deformation at time t=0.1s,0.2s,0.3s,0.4s,0.5s and 0.6 s are depicted in Fig.13.It was observed that the blade deformation is almost constant from t=0.3s to 0.6 s.Therefore,it can be concluded that the solution is a converged solution.

Fig.7.Variation of total deformation with J.

4.2.2.Compositepropeller

Fig.8.Variation of von-Mises stress with J.

Majority of marine propellers currently in use are metallic propellers.However,the advantages with the use of Carbon fiber reinforced plastics for marine propeller are the high strength to weight ratio,resistance to corrosion,superior sound absorption properties,resistance to cavitation damage,high durability,good damping property and flexural strength.Therefore,three composite materials have been chosen and two-way FSI analysis is carried out by replacing the metallic propeller with composite material at J=0.833 and at 792 rpm.Composite materials selected for the analysis are T70 0-epoxy,T1000G/S-Glass hybrid epoxy,and T1000G-epoxy.Only the blades of the metallic propeller are replaced by the composite propeller in the analysis.The properties of the composite propeller are given in Table 2.Maximum equivalent von-Mises stress induced and maximum total deformation have been compared for metal and composite materials in Tables 3 and 4.The stress induced for composite material are in the order of metallic propeller with a clear difference for each composite propeller.The maximum deformation for all the composite materials is more than metallic propeller due to the flexibility of composites.This shows the requirement of two-way FSI analysis in the selection of composite materials for propellers.

Table 2 Composite Material Properties (Matrix-epoxy).

Table 3 Maximum stress induced for different materials in MPa.

Table 4 Maximum total deformations for different material.

4.3.Pressure distribution on blade

Fig.9.von-Mises stress variation with time up to 0.015 s at J=0.833.

Fig.10.Total deformation variation with time up to 0.015 s at J=0.833.

Fig.11.Total deformation variation with time up to 0.6 s at J=0.833.

Fig.12.Contours of deformation (mm) and stress (MPa) at different advance ratio.

The pressure distribution on propeller blade is obtained from two-way FSI analysis is plotted at at J=0.833 and different sections.The results are taken at the last time step where simulation time is 0.6s.Chord wise pressure distribution on suction and pressure side on propeller blade sections is illustrated in Figs.14,15 and 16 at r/R=0.3,0.7,0.9.The value of s/c varies from 0 to 1.0 indicating the location from the leading edge to the trailing edge of the blade.The operating pressure used is 101325 Pascal in the analysis.The free stream pressure defined in the simulation is zero and the free stream velocity is 2.2 m/s correspond to advance ratio 0.833 and it is used as a reference velocity for the calculation of the pressure coefficient.The pressure coefficient value is computed by considering the ratio of the difference of static pressure and free stream pressure to the dynamic pressure.The Cpvalue is computed using the Eq.(5).

Fig.13.Propeller blade deformation at t=0.1 s,0.2 s,0.3 s,0.4 s,0.5 s and 0.6 s.

The pressure distribution plotted is similar [7]to the pressure distribution trend plotted for DTMB 4119 propeller with 0.3048 m diameter.

4.4.Acoustic response

The sound pressure level (SPL) values predicted by two-way FSI at advance ratio of 0.833 have been plotted over the frequency range of 0 to 1000 Hz which is shown in Fig.17.This data is plotted at the receiver point 0.595 m behind the propeller and 0.255 m radially from the longitudinal axis and the location of receiver point is also embodied in the graph.The exponential decrease of SPL values is observed from the plot in the considered frequency range.The maximum value of SPL is 121 dB.Total coupling time simulated is 0.6s and the time step used is 0.0005s.The number of sub steps used in each time step is 2.Therefore,total number of coupling iterations are 2400.In two-way FSI analysis,the data is transferred between fluid flow and transient structural solvers during solution.The data transfer residual plot is shown in Fig.18.The fluid flow data transfer change RMS and transient structural data transfer change RMS are plotted against coupling iterations.This way the two-way FSI analysis can also be used for the acoustic response of the propeller,whereas one-way FSI cannot predict the acoustic response.Rigid propeller analysis can predict acoustic response but actual acoustic response cannot be predicted.Hence it can be concluded that the use of Two-way FSI analysis can accurately predict hydrodynamic,structural and acoustic response simultaneously.

Fig.14.Pressure distribution at r/R=0.3,J=0.833.

Fig.15.Pressure distribution at r/R=0.7,J=0.833.

Fig.16.Pressure distribution at r/R=0.9,J=0.833.

Fig.17.Sound pressure level plot in the frequency range of 0 to 1000 Hz.

Fig.18.Data transfer between fluid flow and transient structural solvers.

5.Conclusions

A two-way fluid-structure interaction study on a 0.2 m diameter DTMB 4119 propeller is carried out at different advance ratios,for different materials and the conclusions drawn from the computational analysis are

·The computational results of hydrodynamic parameters are validated with the experimental results in the literature and twoway FSI results are closer to the experimental results than oneway FSI results.

·The thrust coefficient and moment coefficient are almost same at an advance ratio for both one-way FSI and two-way FSI analysis.

·The stress and deformation values computed from the two-way fluid structure interaction are decreasing with the increase in advance ratio.Stresses computed from the two-way FSI analysis are higher than one-way FSI for all advanced ratios.

·The total deformation at the tip of the blades and von-Mises stress induced at the root of the blade is decreased with the increase in advance velocity.

·One-way FSI analysis can be selected for propeller analysis only when the initial results of transient solution are not important.

·The initial structural response cannot be predicted accurately by one-way FSI analysis,hence,it is recommended to use two-way FSI as the peak value of the stress and deformation are important in the selection of propeller material and design.

·Metallic propeller is replaced by three composite materials and investigated the feasibility of replacement of metal using composite material.It is evident that all three materials can withstand the stresses induced in the propeller.It is recommended to replace the metallic propeller with composite material based on low cost and availability

·Two-way FSI analysis can be better predict the off-design hydrodynamic,structural and acoustic responses of the propellers and also,two-way FSI is the only type of analysis that predict the acoustic response of the propeller and simultaneously the hydrodynamic and structural response.However,Two-way FSI analysis is computationally challenging to simulate and need more computational effort.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.