Highlights:Graphical/Tabular Abstract  Computational FluidDynamics  Noise Sources  Lighthill Curle Method The flow noise generated by a generic underwater vehicle is modeled and solved in a numerical environment. By using the Large Eddy Simulation (LES), the hydrodynamic analysis is performed using the finite volume methods and the acoustic analogies modeling the sound propagation. Sound pressure levels, sound direction, noise spectra and acoustic trace are found in the fluid environment. By using the pressure-based commercial code, the flow dynamics equations are solved in filtering process and the pressure obtained from hydrodynamic solution is defined as an acoustic source. Along with this, in order to be able to verify the method, a numerical process was created which will be evaluated considering the experimental studies in the literature. The numerical results of the thrust and torque curves at different rpms and speeds for the 4382 propeller were compared with test data. In addition, the amplitude levels of the noise harmonics generated by the VP1304 propeller are obtained by hybrid method at the receivers in the numerical environment and the results are compared with the test data. With the verification of the current method, the noise characteristics of the underwater vehicle were found by the Lighthill-Curle method and the classification of noise sources was performed using hydrodynamic sources. Thus, the feasibility and application of current work, which is an important criterion in the design and development phases, has been demonstrated and developed in this paper. As given in Figure A. the noises from propulsion can be implemented to the Lighthill approach to find the main noise characteristics of the vehicle in a numerical manner. Figure A. The noises existing from propulsion system Purpose: This section should state the purpose of the research. Times New Roman fonts 9 pts Theory and Methods:Ligthill-Curle method is an acoustical approach to find the noise characteristics of an moving object underwater. This method can be used to visualize the whole spectrum range and the proper Results:The dominant noise sources are from propeller and wake region, so acoustical analogy can be used easily. Conclusion:Experimental validation has to be provided further to compare noise characteristics of vehicle

This paper presents results of computation of a unique propeller design for underwater vehicles using an original in-house algorithm which is developed for the problems of fluid dynamics. Specific software based on finite volume calculations are used to validate design procedure. Conventional propellers having experimental results are good choice to investigate the convenience of solutions. Cavitation tunnel test results of two types of conventional propeller namely P-4382 and P-4119 were considered as a test-case study. The characteristic performances of those were all compared with CFD analysis for different conditions to realize the effects of mesh generation, discretization method and turbulence model in numerical process. Design criteria for unique propeller were selected according to underwater vehicle performance and its requirements. Then the method performed in validation stage was entirely implemented to the new design to observe its performance curves. The results show that this new propeller design is capable of providing desired thrust, vehicle velocity and power output with high efficiency for underwater vehicle. Algorithm implementation, mesh generation, turbulence models and solution methods in CFD process are so suitable that results of analyses are matching with experiments.