Propeller Open Water Characteristics Research Articles

A Calibration Study with CFD Methodology for Self-Propulsion Simulations at Ship Scale

This paper summarises the main findings from the full-scale Computational Fluid Dynamics (CFD) analyses conducted at SINTEF Ocean on the case of MV REGAL, which is one of the benchmark vessels studied in the ongoing joint industry project JoRes. The numerical approach is described in detail, and comparative results are presented regarding the propeller open water characteristics, ship towing resistance, and ship self-propulsion performance. The focus of numerical investigations is on the assessment of the existing simulation best practises applied to a ship-scale case in a blind simulation exercise and the performance thereof with different turbulence modelling methods. The results are compared directly with full-scale performance predictions based on model tests conducted at SINTEF Ocean and sea trials data obtained in the JoRes project.

Manoeuvring simulations of Autonomous Underwater Vehicle using quaternion

The dynamics of an autonomous underwater vehicle (AUV), which can perform manoeuvres with pitch angles in the range of 90° is investigated in this paper. The purpose of the AUV is to perform station keeping manoeuvre at about 90° pitch angle by varying propeller revolution. The AUV is launched / retrieved in horizontal orientation. Quaternion mathematics, 4 quadrant propeller open water characteristics and PID controller for propeller revolution are incorporated in manoeuvring mathematical model for this purpose. A procedure for optimizing the gain coefficients for the PID controller is developed using the manoeuvring mathematical model. Two design configuration of the AUV are investigated, positively buoyant and negatively buoyant. It is shown that both the optimal gain coefficients for the PID controller for propeller revolution and dynamic response of the AUV are different for each design configuration.

Numerical study on the scale effect of high-skew propeller E1619

In this study, a large skewed propeller INSEAN E1619 model with 7 blades working in open water conditions has been numerically simulated by an inhouse URANS (Unsteady Reynolds-averaged Navier-Stokes) code coupled with dynamic overset grid approach. Grid and time-step sensitivity analysis of the propeller model has been conducted and the numerical results have been compared with available experimental data performed by INSEAN aimed to validate the numerical method. Propeller open water characteristics have been compared for models with different scales at given advance coefficient to evaluate scale effect of this high-skew propeller. Non-dimensional pressures on different scaled models have been compared between models with different scales. Results show that propeller’s thrust and torque increase with the increase of propeller scale, which is mainly due to the increase of pressure component. It could be found that the pressure on suction side near the trailing edge decreases with the increase of propeller’s scale.

Different Approaches in Simulation Propeller Open Water Characteristics using CFD Method

Different Approaches in Simulation Propeller Open Water Characteristics using CFD Method

Different Approaches in Simulation Propeller Open Water Characteristics using CFD Method

Different Approaches in Simulation Propeller Open Water Characteristics using CFD Method

Experimental and Numerical Investigation of DARPA Suboff Submarine Propelled with INSEAN E1619 Propeller for Self-Propulsion

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. 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. 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. To experimentally investigate the submarine form, a self-propulsion experimental setup is designed and manufactured. Resistance and self-propulsion experiments are conducted in Istanbul Technical University Ata Nutku Ship Model Testing Laboratory. Resistance tests are carried out for three different speeds, and the results show good agreement with the published experimental results. Propulsion tests are conducted by using the load-varying self-propulsion test method for constant speed and seven different propeller rotation rates. Rotational speed, thrust, and torque forces at self-propulsion point are investigated. For the numerical computations a commercial Computational Fluid Dynamics (CFD) code is used. Propeller open water characteristics and nondimensional velocities behind the propeller are calculated. 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.

Prediction of Propeller Open Water Characteristics for High Speed Boat by CFD Method

Nowadays with the development of computational resources, calculating the open water characteristics of the propeller using Computational Fluid Dynamics (CFD) has been used widely at the initial design stage because of relatively accurate result, time and cost saving, in comparison with experimental approach. This paper presents the results of computational evaluation of propeller open water characteristics for high speed boat, based on steady RANSE flow model with rotating reference frame approach. The effects of mesh density, mesh generation are analyzed in order to improve obtained numerical results. The well-known Gawn propeller series, that is often used for high speed vessel is used to verify and validate the accuracy of case studies. In this study, the authors use the commercial solver Star CCM+ by SIEMENS.

Numerical Study on Flow Around Modern Ship Hulls with Rudder-Propeller Interactions

Reducing the fuel consumption of ships presents both economic and environmental gains. Although in the past decades, extensive studies were carried out on the flow around ship hull, it is still difficult to calculate the flow around the hull while considering propeller interaction. In this paper, the viscous flow around modern ship hulls is computed considering propeller action. In this analysis, the numerical investigation of flow around the ship is combined with propeller theory to simulate the hull-propeller interaction. Various longitudinal positions of the rudder are also analyzed to determine the effect of rudder position on propeller efficiency. First, a numerical study was performed around a bare hull using Shipflow computational fluid dynamics (CFD) code to determine free-surface wave elevation and resistance components. A zonal approach was applied to successively incorporate “potential flow solver” in the region outside the boundary layer and wake, “boundary layer solver” in the thin boundary layer region near the ship hull, and “Navier-Stokes solver” in the wake region. Propeller open water characteristics were determined using an open-source MATLAB code OpenProp, which is based on the lifting line theory, for the moderately loaded propeller. The obtained open water test results were specified in the flow module of Shipflow for self-propulsion tests. The velocity field behind the ship was recalculated into an effective wake and given to the propeller code that calculates the propeller load. Once the load was known, it was transferred to the Reynolds-averaged Navier-Stokes (RANS) solver to simulate the propeller action. The interaction between the hull and propeller with different rudder positions was then predicted to improve the propulsive efficiency.

An experimental method to identify a component of wave orbital motion in propeller effective inflow velocity and its effects on load fluctuations of a ship main engine in waves

Improvements of estimation accuracy on propeller torque fluctuations in waves will contribute assessments on safe operation of a ship main engine as in adverse sea condition. The propeller torque and thrust in waves can be estimated by propeller effective inflow velocity in waves, using the propeller open-water characteristics. Fluctuation components in the mathematical model of the propeller effective inflow velocity in waves can be composed of two components, respectively caused by ship surge motion and wave orbital motion at propeller position. In this study, an experimental method by the model test to directly identify the characteristics of the component by the wave orbital motion is newly proposed. Furthermore, the free-running model test in regular waves, using a simulator of the marine diesel engine which manages the shaft speed of the motor on a ship model as behaving the actual diesel engine, is carried out to obtain realistic torque fluctuations for comparisons of the estimated results applying the proposed identification method. Through comparisons of estimated fluctuations with the measured results, the proposed approach for the component of the inflow velocity due to wave orbital motion is successfully validated.

Numerical simulation of propeller open water characteristics using RANSE method

The paper presents the results of numerical simulations of propeller open water characteristics by using RANSE method with rotating reference frame approach. The effects of grid type, mesh density and turbulence models on simulation results are analyzed. The well-known Potsdam Propeller PPTC test case is used to verify and validate the accuracy of case studies. At the end, the assessment and recommendation for choosing grid type and turbulence model from the point of view of the level of accuracy are given. The solver used in this study is the commercial package Star-CCM+from SIEMENS.

Numerical Prediction of Propeller-Hull Interaction Characteristics Using RANS Method

Abstract The paper presents the results of computational evaluation of the hull-propeller interaction coefficients, also referred to propulsive coefficients, based on the unsteady RANS flow model. To obtain the propulsive coefficients, the ship resistance, the open-water characteristics of the propeller, and the flow past the hull with working propeller were computed. For numerical evaluation of propeller open-water characteristics, the rotating reference frame approach was used, while for self-propulsion simulation, the rigid body motion method was applied. The rotating propeller was modelled with the sliding mesh technique. The dynamic sinkage and trim of the vessel were considered. The free surface effects were included by employing the volume of fluid method (VOF) for multi-phase flows. The self-propulsion point was obtained by performing two runs at constant speed with different revolutions. The well-known Japan Bulk Carrier (JBC) test cases were used to verify and validate the accuracy of the case studies. The solver used in the study was the commercial package Star-CCM+ from SIEMENS.

Numerical and experimental investigation of propulsion in waves

The effects of head waves on propulsion characteristics of a single and a twin screw ship were investigated based on a Reynolds-averaged Navier-Stokes (RANS) solver and physical tests. Initially, propeller open water characteristics were determined in a homogeneous inflow. Next, computations of the towed models without propeller(s) in calm water and in waves were performed to obtain calm water resistances and waves added resistances. Finally, forces acting on the self-propelled models in calm water and in regular head waves were computed. Using obtained results propulsion characteristics in calm water and in waves were determined. Computations were performed using a RANS based flow-solver coupled with the nonlinear six-degrees-of-freedom equations of motion. When needed, the sliding interface method was used, enabling rotation of the geometrically modeled propeller. All computations were performed on the same numerical grid to keep errors originating from different spatial and temporal discretizations as small as possible. Grid studies were conducted to evaluate discretization errors. Computational results were compared to experimental results obtained from physical model tests. It was shown that the RANS solver is capable of investigating the propulsion behavior of a ship in regular head waves. Fair agreement between numerical and experimental results was obtained.

Computations of the propeller open water characteristics using the SOLAGA computer program. Predictions of the cavitation phenomenon

This paper presents the theoretical model and numerical methods which are applied in computer program SOLAGA for computations of viscous flow around ship propeller as well as for modelling of cavitation phenomenon. The model presented in the article is based on mass conservation equation and Reynolds averaged Navier-Stokes equation, the turbulent viscosity is approximated with the use of Spalart-Allmaras turbulent model. The numerical model used for solving the system of main equations is based on Finite Volume Method. The procedures for cavitation predictions applied in the SOLAGA program are based on travelling bubble model. This paper presents the results of computations of KT, KQ characteristics for conventional and skewed propeller. The results are compared with the data obtained from experiment. The results of computation of cavitation for the skewed propeller are presented as well.

Some Improvements of Ship Power Prediction Method in the IHI Towing Tank

For further improvements of the ship power prediction method by model tests, there were many rooms to obtain the accuracy meeting the present designers' demands. In the IHI towing tank, since its establishment in 1966, steady achievements have been done to satisfy their demands. This paper presents almost all of the measures of improvements conducted and the results obtained in IHI, content of which extends from the facility and test practice to the model-ship correlation. Among them, first it is insisted that the reduction of influence of Reynolds number and disturbances such as the residual current in the tank upon the test results is quite effective for increasing accuracy. Second a theoretical estimation method of propeller open-water characteristics is proposed from the view point of correcting the influence of Reynolds number on its performance. Finally taking the influence of interference between Reynolds number of hull and the propeller loading into account, a new method of ship-model correlation for the effective wake is given. As a result, the average errors of model test results decrease less than 1% and the reliability of predicted ship power gets to more than 97%.

Estimation of Propeller Open-Water Characteristics Based on Quasi-Continuous Method

A numerical method to estimate propeller open-water characteristics based on Quasi-Continuous Method (QCM) is presented. QCM was originally developed by Lan for solving planar thin wing problems. QCM has both advantages of continuous loading method and discrete loading method; loading distribution is assumed to be continuous in chordwise direction and stepwise constant in spanwise direction. Simplicity and flexibility of discrete loading method are also retained.In the present paper, explanations are made first on the essential features of QCM for planar wings and then its application to marine propellers is described in detail. Some numerical results on the propeller open-water characteristics for conventional and skewed propellers showed good agreement with those of experiments.