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Underwater sound reference detachment5/26/2023 Self-propulsion point of the submarine and propeller assembly is also solved numerically and the results are compared with the results obtained from the experiments, and it is seen that especially the propeller rate of revolution and thrust force are predicted with very good approximation.Īdaptive line enhancers (ALEs) have been widely used in passive sonars for enhancing narrowband discrete components (known simply as lines or tonals) radiated by surface or underwater targets. Propeller open water characteristics and nondimensional velocities behind the propeller are calculated. For the numerical computations a commercial Computational Fluid Dynamics (CFD) code is used. Rotational speed, thrust, and torque forces at self-propulsion point are investigated. Propulsion tests are conducted by using the load-varying self-propulsion test method for constant speed and seven different propeller rotation rates. Resistance tests are carried out for three different speeds, and the results show good agreement with the published experimental results. Resistance and self-propulsion experiments are conducted in Istanbul Technical University Ata Nutku Ship Model Testing Laboratory. To experimentally investigate the submarine form, a self-propulsion experimental setup is designed and manufactured. In this article, the self-propulsion characteristics of the DARPA Suboff submarine model with INSEAN E1619 propeller obtained with experimental and numerical methods are presented and discussed by means of Taylor wake fraction, thrust deduction, hull efficiency, relative rotative efficiency, and propulsive efficiency. Although there are several numerical studies where the DARPA Suboff submarine is used in combination with E1619 propeller there are no experimental data available in open literature for the self-propulsion condition. The Defense Advanced Research Projects Agency (DARPA) Suboff Submarine propelled by the Italian Ship Model Basin (INSEAN) E1619 propeller is extensively used in submarine validation studies. In addition, the structure-borne noise under distributed pulsation pressure is mainly radiated from the conical end caps and the stern, while the flow noise is mainly radiated from the cylindrical hull. For the calculation conditions of low-speed navigation, the sound pressure level (SPL) of the structure-borne noise is higher than that of the flow noise. In the studied frequency range, the spectrum characteristics of the structure-borne noise of the submarine are mainly contributed by the longitudinal mode of the shafting system, in-phase mode of the rotor blades, and the characteristic peaks of the pulsation pressure. The spectrum characteristics of the flow noise are similar to those of the pulsation pressure, with peaks at BPF and its multiples. Finally, the structure-borne noise of coupled pump-jet– shafting– SUBOFF system under distributed pulsation pressure is predicted by coupled finite element method (FEM) and BEM. Then, the pulsation pressure on the pump-jet and the submarine are obtained by the verified CFD model, which is transferred to obtain the flow noise. Firstly, the numerical approaches of computational fluid dynamics (CFD) employed to predict the pulsation pressure and the boundary element method (BEM) employed to calculate the flow noise are verified. This study presents the characteristics of the flow noise of a fully appended SUBOFF propelled by a pump-jet and the comparison with the structure-borne noise.
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