Numerical Study on Multiple-Blade-Rate Unsteady Propeller Forces for Underwater Vehicles

2021 ◽  
pp. 1-20
Author(s):  
Kenshiro Takahashi ◽  
Jun Arai ◽  
Takayuki Mori
Keyword(s):  
Numerical Study ◽  
Underwater Vehicles ◽  
Marine Propellers ◽  
Defense Systems ◽  
Detection Technology ◽  
Acoustic Signature ◽  
Océanographic Survey ◽  
Propeller Blades ◽  
Marine Vessels ◽  
Blade Loads

The unsteady propeller forces of an underwater vehicle were numerically simulated using computational fluid dynamics to investigate the effects of the axial location of the stern planes. A benchmark study was undertaken using a three-bladed propeller; experimental results of the nominal inflow wake profile were analyzed and the unsteady propeller forces were measured. The numerical method was applied to predict the unsteady propeller forces in the SUBOFF model’s wake by varying the axial locations of the stern planes. Several remarks were made on the primary harmonics of the hull’s wakes and blade-rate propeller forces. Introduction The hydroacoustic noise, which matches multiples of the number of propeller blades and its rotational speed, known as “blade-rate (BR) noise,” has been increasingly used to manage hydroacoustics for naval vessels. BR noise can be caused by alternating blade loads owing to fluctuations in the angle of attack of the blades because marine propellers are operated in the nonuniform wake of ships’ hulls. The unsteady blade load produces unsteady propeller forces that are transmitted via the propeller shaft and bearing, thus producing undesirable vibration and noise. Although the resultant BR noise is a common issue for marine vessels, in particular, submarines and other underwater vehicles deployed for undersea defense systems and oceanographic survey systems require strict specifications for the acoustic signature. Therefore, the unsteady propeller forces must be improved for reduced detectability, because the vehicles should be able to operate without being discovered while sonar detection technology continues to improve.

Experimental and Numerical Study on Propulsive Performance of AUV

2010 ◽  
Author(s):  
Hiroyoshi Suzuki ◽  
Tomoya Inoue ◽  
Yoshitaka Watanabe ◽  
Hiroshi Yoshida ◽  
Risa Kitamoto ◽  
...  
Keyword(s):  
Numerical Study ◽  
Autonomous Underwater Vehicles ◽  
Underwater Vehicles ◽  
Long Distance ◽  
Hull Form ◽  
Océanographic Survey ◽  
Resistance Performance ◽  
Resistance Form ◽  
The Relationship ◽  
Mass Form

Recently, several underwater vehicles (UVs) including autonomous underwater vehicles (AUVs) and remotely operated vehicles (ROVs) have been developed. The purpose that such UVs are applied is various and the required performance for the UVs are also various. For example, they are oceanographic survey with long-distance cruising, plankton investigatory with high maneuverability and so on. Therefore, suitable UV for the mission is should be designed. In the above examples, UV that has the low resistance form is suitable for long-distance cruising; UV with low added mass form is suitable for plankton investigatory. Form the above viewpoint; we began working on a project to improve the UV’s hull form. Firstly, we focus on the resistance performance of UV within the resistance performance and maneuverability of UV. Using experimental and numerical methods, the relationship between the resistance performance and the UV’s hull form are investigated. In this paper, the part of the above results is introduced.

A 2.5D numerical study on open water hydrodynamic performance of a Voith-Schneider propeller

2019 ◽  
Vol 20 (6) ◽  
pp. 617
Author(s):  
Mohammad Bakhtiari ◽  
Hassan Ghassemi
Keyword(s):  
Numerical Method ◽  
Thrust Force ◽  
Numerical Study ◽  
Open Water ◽  
Hydrodynamic Performance ◽  
Maximum Efficiency ◽  
Water Efficiency ◽  
Blade Thickness ◽  
Unsteady Rans ◽  
Marine Vessels

Marine cycloidal propeller (MCP) is a special type of marine propulsors that provides high maneuverability for marine vessels. In a MCP, the propeller axis of rotation is perpendicular to the direction of thrust force. It consists of a number of lifting blade. Each blade rotates about the propeller axis and simultaneously pitches about its own axis. The magnitude and direction of thrust force can be adjusted by controlling the propeller pitch. Voith-Schneider propeller (VSP) is a low-pitch MCP with pure cycloidal blade motion allowing fast, accurate, and stepless control of thrust magnitude and direction. Generally, low-pitch cycloidal propellers are used in applications with low speed maneuvering requirements, such as tugboats, minesweepers, etc. In this study, a 2.5D numerical method based on unsteady RANS equations with SST k-ω turbulent model was implemented to predict the open water hydrodynamic performance of a VSP for different propeller pitches and blade thicknesses. The numerical method was validated against the experimental data before applying to VSP. The results showed that maximum open water efficiency of a VSP is enhanced by increasing the propeller pitch. Furthermore, the effect of blade thickness on open water efficiency is different at various advance coefficients, so that the maximum efficiency produced by the VSP decreases with increasing blade thickness at different propeller pitches.

Robotic Solutions Applied to Production and Measurement of Marine Propellers

2012 ◽  
Author(s):  
Javier Cavada ◽  
Fernando Fadón
Keyword(s):  
Industrial Robots ◽  
Cell Alignment ◽  
Marine Propellers ◽  
Tool Positioning ◽  
Cad Cam ◽  
Principal Factors ◽  
Propeller Blades ◽  
The Individual ◽  
Accuracy And Repeatability ◽  
Individual Design

Over the past decades, robots have emerged as a valuable technological solution for multiple highly complex industrial processes, and the manufacture of marine propellers has not been an exception. Majority of the propellers being produced worldwide are custom-designed products aiming to satisfy each ship’s propulsion requirements. Such geometrical diversity is a considerable challenge when traditionally manual manufacturing processes like hand-grinding and polishing need to be automated. In several market-leading propeller manufacturers within Europe and Asia, industrial robots are being applied for widely diverse operations such as milling polystyrene blocks to make moulding patterns, grinding out the excess material in the blade surfaces, or polishing the complete propellers’ surface before their final verification. Propeller blades are customized products, formed by curved and warped surfaces, requiring minimum 5 axes to be smoothly polished, and this can be easily achieved with a robot cell where the CAD/CAM data coming from the individual design are directly translated into robotic parameters. While this solution has demonstrated to be perfectly capable to comply with the marine propellers finishing tolerances, which are internationally defined by ISO 484 standard rules [6], robotic solutions for propeller measurement have not been successfully implemented within this specific industry due to reasons like lack of accuracy and repeatability. This paper analyses the root causes behind this problem, identifying the calibration process, the cell alignment method and the tool positioning as the principal factors resulting in this low measuring repeatability. Findings explained by the authors are the outcome of several practical measuring tests made on real marine propellers within ABB and Fanuc robot cells. This paper concludes offering solutions to reduce the inaccuracies caused by the mentioned factors, and recommending what type of marine propellers are more suitable to be measured with industrial robots, on the basis of ISO 484 requirements for each customized design. Moreover, suggestions for further research on this specific measuring application are provided in the concluding chapter.

scholarly journals An experimental and numerical study of the vortices generated by hydrofoils

2009 ◽  
Vol 16 (3) ◽  
pp. 11-17 ◽  
Author(s):  
J. Szantyr ◽  
R. Biernacki ◽  
P. Flaszyński ◽  
P. Dymarski ◽  
M. Kraskowski
Keyword(s):  
Velocity Field ◽  
Cross Sections ◽  
Numerical Study ◽  
Turbulence Models ◽  
Marine Propeller ◽  
Flow Conditions ◽  
Tip Vortices ◽  
Cavitation Tunnel ◽  
Computer Codes ◽  
Propeller Blades

An experimental and numerical study of the vortices generated by hydrofoils The article presents the results of the research project concerning the process of formation of the tip vortices shed from hydrofoils of different geometry in different flow conditions. Three hydrofoils resembling the contemporary marine propeller blades have been selected for the study. The experimental part of the project consisted of the LDA measurements of the velocity field in three cross-sections of the vortex generated by the hydrofoils in the cavitation tunnel. The numerical part of the project consisted of calculations of the corresponding velocity field by means of three computer codes and several selected turbulence models. The comparative analysis of the experimental and numerical results, leading to the assessment of the accuracy of the numerical methods, is included.

scholarly journals Numerical Study of the Effect of Wing Position on the Dynamic Motion Characteristics of an Underwater Glider

2021 ◽  
Vol 28 (2) ◽  
pp. 4-17
Author(s):  
Xiangcheng Wu ◽  
Pengyao Yu ◽  
Guangzhao Li ◽  
Fengkun Li
Keyword(s):  
Numerical Study ◽  
Autonomous Underwater Vehicles ◽  
Underwater Vehicles ◽  
Underwater Glider ◽  
Dynamic Motion ◽  
Biological Oceanography ◽  
Underwater Gliders ◽  
Movement Performance ◽  
Motion Characteristics ◽  
The Relationship

Abstract Underwater gliders are winged, autonomous underwater vehicles that are broadly applied in physical and biological oceanography. The position of the wing has an important effect on the movement performance of the underwater glider. In this paper, the dynamic motion of a series of underwater glider models with different longitudinal wing positions are simulated, which provides guidance for the design of underwater gliders. The results show that when the net buoyancy is constant, the wing position affects the gliding angle, but does not affect the relationship between the gliding angle and the gliding speed. In addition, the farther the wing position of the glider is from the buoyancy centre, the longer it takes for the attitude of a glider to change, whether the wing is in front of, or behind, the buoyancy centre.

scholarly journals Advances in passive acoustic detection, localization, and tracking applied to unmanned underwater vehicles

2022 ◽  
Author(s):  
◽  
Kristen R. Kita
Keyword(s):  
High Frequency ◽  
Underwater Vehicles ◽  
Broadband Noise ◽  
Cavitation Noise ◽  
Unmanned Underwater Vehicles ◽  
Motor Noise ◽  
Acoustic Signature ◽  
Range Rate ◽  
Passive Acoustic ◽  
Localization And Tracking

Detection, classification, localization, and tracking (DCLT) of unmanned underwater vehicles (UUVs) in the presence of shipping traffic is a critical task for passive acoustic harbor security systems. In general, vessels can be tracked by their unique acoustic signature due to machinery vibration and cavitation noise. However, cavitation noise of UUVs is considerably quieter than ships and boats, making detection significantly more challenging. In this thesis, I demonstrated that it is possible to passively track a UUV from its highfrequency motor noise using a stationary array in shallow-water experiments with passing boats. First, causes of high frequency tones were determined through direct measurements of two UUVs at a range of speeds. From this analysis, common and dominant features of noise were established: strong tones at the motor’s pulse-width modulated frequency and its harmonics. From the unique acoustic signature of the motor, I derived a high-precision, remote sensing method for estimating propeller rotation rate. In shallow-water UUV field experiments, I demonstrated that detecting a UUV from motor noise, in comparison to broadband noise from the vehicle, reduces false alarms from 45% to 8.4% for 90% true detections. Beamforming on the motor noise, in comparison to broadband noise, improved the bearing accuracy by a factor of 3.2×. Because the signal is also high-frequency, the Doppler effect on motor noise is observable and I demonstrate that range rate can be measured. Furthermore, measuring motor noise was a superior method to the “detection of envelope modulation on noise” algorithm for estimating the propeller rotation rate. Extrapolating multiple measurements from the motor signature is significant because Bearing-Doppler-RPM measurements outperform traditional bearing-Doppler target motion analysis. In the unscented Kalman filter implementation, the tracking solution accuracy for bearing, bearing rate, range, and range rate improved by a factor 2.2×, 15.8×, 3.1×, and 6.2× respectively. These findings are significant for improving UUV localization and tracking, and for informing the next-generation of quiet UUV propulsion systems.

Numerical Study on the Performance Analysis and Vibration Characteristics of Flexible Marine Propeller

2020 ◽  
Author(s):  
Kumar S. Ashok ◽  
Subramanian V. Anantha ◽  
R. Vijayakumar
Keyword(s):  
Performance Analysis ◽  
Numerical Study ◽  
Open Water ◽  
Simulation Method ◽  
Mode Shapes ◽  
Thrust Coefficient ◽  
Fluid Structure ◽  
Marine Propellers ◽  
Water Characteristics ◽  
Wet Condition

Abstract This paper addresses the hydro-elastic performance of two composite marine propellers at operating condition and compares the results with conventional materials. The study involves three stages namely, design and development of a B series propeller, hydrodynamic and structural performance analysis in uniform flow and free vibration test both in dry and wet condition. In order to perform the hydro-elastic based fluid structure interaction (FSI), Co-Simulation method was adopted to couple Reynolds Averaged Navier-Strokes Equation (RANSE) based Computational Fluid Dynamics (CFD) solver and finite element method (FEM) solvers. The open water characteristics such as thrust coefficient (KT), torque coefficient (KQ), and open water efficiency (ηO) were analyzed as a function of advance velocity (J) of the propeller. A detailed study of the various blade materials by varying mechanical properties are presented. The results obtained show the variation of stress and deflection on the blade, along with the influence of the blade deformation on the performance of propeller. The vibration behaviour of the propellers were also analysed by Block-Lanczos method in FEM solver to obtain the natural frequencies and the mode shapes using Acoustic Fluid-Structure Coupling method for both dry and wet condition. Results showed that composite propeller have better hydro-dynamic property and lower vibration than metal propeller.

scholarly journals A Comparison of Physical and Numerical Modeling of Homogenous Isotropic Propeller Blades

2020 ◽  
Vol 8 (1) ◽  
pp. 21 ◽  
Author(s):  
Luca Savio ◽  
Lucia Sileo ◽  
Sigmund Kyrre Ås
Keyword(s):  
Numerical Modeling ◽  
Open Water ◽  
Computational Approach ◽  
Experimental Setup ◽  
Fluid Structure ◽  
Towing Tank ◽  
Design Procedures ◽  
Structure Interaction ◽  
Marine Propellers ◽  
Propeller Blades

Results of the fluid-structure co-simulations that were carried out as part of the FleksProp project are presented. The FleksProp project aims to establish better design procedures that take into account the hydroelastic behavior of marine propellers and thrusters. Part of the project is devoted to establishing good validation cases for fluid-structure interaction (FSI) simulations. More specifically, this paper describes the comparison of the numerical computations carried out on three propeller designs that were produced in both a metal and resin variant. The metal version could practically be considered rigid in model scale, while the resin variant would show measurable deformations. Both variants were then tested in open water condition at SINTEF Ocean’s towing tank. The tests were carried out at different propeller rotational speeds, advance coefficients, and pitch settings. The computations were carried out using the commercial software STAR-CCM+ and Abaqus. This paper describes briefly the experimental setup and focuses on the numerical setup and the discussion of the results. The simulations agreed well with the experiments; hence, the computational approach has been validated.

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