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Neil Bose - One of the best experts on this subject based on the ideXlab platform.

  • Preliminary blade load measurements on a model propeller in ice
    2020
    Co-Authors: Corwyn Moores, Neil Bose, Brian Veitch, Stephen J. Jones, J. I. Bell, John Carlton
    Abstract:

    Preliminary results of a series of model scale propeller experiments are presented. A large (0270mm) model of a highly skewed controllable pitch propeller was tested in both open water and ice covered water in the ice tank at the Institute for Marine Dynamics. Both the open water and ice experiments were done at four different pitch settings, each over a range of Advance Coefficient. The ice strength and the depth cut into the ice by the propeller were varied in the ice tests. The main aims of the experiments were to measure the effects of these variables on blade loads, in addition to their effects on shaft loads. Shaft loads were measured using conventional dynamometry. Loads on one blade were measured using a hubmounted blade dynamometer designed and built for these tests. The blade dynamometer is described and some preliminary shaft and blade load measurements are presented and discussed.

  • Performance of a family of surface piercing propellers
    Royal Institution of Naval Architects Transactions, 2020
    Co-Authors: M Fernando, Neil Bose, A Scamardella, Brian Veitch
    Abstract:

    Tests on a systematic series of surface piercing propellers were analyzed to study some aspects of scaling the performance of this kind of propulsor. In particular, the influence of the Weber number, depth of immersion, and shaft rake are discussed and results for variations in these conditions are presented. Regression equations are given of the relationship between critical Advance Coefficient and Weber number, and of the thrust and torque Coefficients at Advance Coefficients above the critical values. This work is the result of co-operative research on the scaling of the performance of surface piercing propellers that was jointly undertaken by the University of Genoa, University of Naples, Memorial University of Newfoundland, and the Institute for Marine Dynamics, NRC.

  • Numerical investigation of propulsive characteristics of podded propellers
    2020
    Co-Authors: Islam, R Taylor, J Quinton, Neil Bose, Brian Veitch, Bruce Colbourne
    Abstract:

    Numerical investigations were performed to predict effects of propeller hub taper angle and pod geometry configurations on propulsive performance. An existing time domain panel method code was extended to handle the simulation tasks. The effect of taper angle was examined in terms of shaft thrust Coefficient, KT, and torque Coefficient, KQ, for different taper angles of -15° (pull/tractor configuration) and +15° (push configuration). The predicted pressure distribution was also analyzed to investigate the effect of taper ratio on pressure Coefficient, Cp, at the blade root section. The effects of pod-strut geometry on KT and KQ of a propeller with taper angles of 15° and 20° with two pods both in push configuration were examined. A complementary experimental study of the effects of taper angle on propulsive performance was also conducted for 15° and 20° taper angles in push configuration. Numerical predictions and experimental measurement showed a good agreement over a wide range of Advance Coefficients from the bollard pull condition to the design Advance Coefficient of about 1.0.

  • Dynamic Positioning Thruster Near Wake Hydrodynamic Characteristics at Near Bollard Pull
    Journal of Ship Research, 2009
    Co-Authors: S El Lababidy, Neil Bose, Dan Walker
    Abstract:

    The knowledge of the hydrodynamic characteristics and momentum effects of the flow of dynamic positioning (DP) thrusters are important factors in the design of structures around the DP thrusters and in improving DP system reliability. In the present study, the flow field around a DP thruster model was precisely measured in a cavitation tunnel using a two-component laser Doppler velocimetry (LDV) system. These experiments were carried out with and without a nozzle at three different axial planes up to 1.5 diameters downstream, and the results are presented here for a pitch/diameter ratio of 1.2 at near bollard pull operating conditions (J = 0.4 and J = 0.45). This paper shows and compares the results of the DP thruster near wake hydrodynamic and momentum characteristics when operating with and without a nozzle at two different low Advance Coefficient values.

  • Experimental study on a model azimuthing podded propulsor in ice
    Journal of Marine Science and Technology, 2008
    Co-Authors: Jungyong Wang, Neil Bose, Stephen J. Jones, Ayhan Akinturk, Yun Young Song, Ho Hwan Chun
    Abstract:

    The objective of this study was to investigate the performance of a model azimuthing podded propulsor in ice-covered water. Model tests were carried out with two different depths of cut into the ice (15 and 35 mm), two different ice conditions (presawn and pack ice conditions), and four different azimuthing angles. The depth of cut is the maximum penetration depth of the propeller blade into the ice block. The 0.3-m-diameter model propeller was operated in a continuous ice milling condition. Ice loads were measured by several sensors which were installed in various positions on the model. Six one-axis pancake-style load cells on the top of the model measured the global loads and two six-component dynamometers were installed on the shaft to measure the shaft loads. One six-component dynamometer was attached to the one of the propeller blades inside the hub to measure the blade loads. The pod unit and propeller performance in ice are presented. Ice-related loads, which were obtained when the blade was inside the ice block, are introduced and discussed. During the propeller–ice interaction, a blade can experience the path generated by the previous blade, which is called the shadowing effect. The effects of shadowing, depth of cut, azimuthing angle, and Advance Coefficient on propulsor performance are presented and discussed.

Brian Veitch - One of the best experts on this subject based on the ideXlab platform.

  • Preliminary blade load measurements on a model propeller in ice
    2020
    Co-Authors: Corwyn Moores, Neil Bose, Brian Veitch, Stephen J. Jones, J. I. Bell, John Carlton
    Abstract:

    Preliminary results of a series of model scale propeller experiments are presented. A large (0270mm) model of a highly skewed controllable pitch propeller was tested in both open water and ice covered water in the ice tank at the Institute for Marine Dynamics. Both the open water and ice experiments were done at four different pitch settings, each over a range of Advance Coefficient. The ice strength and the depth cut into the ice by the propeller were varied in the ice tests. The main aims of the experiments were to measure the effects of these variables on blade loads, in addition to their effects on shaft loads. Shaft loads were measured using conventional dynamometry. Loads on one blade were measured using a hubmounted blade dynamometer designed and built for these tests. The blade dynamometer is described and some preliminary shaft and blade load measurements are presented and discussed.

  • Performance of a family of surface piercing propellers
    Royal Institution of Naval Architects Transactions, 2020
    Co-Authors: M Fernando, Neil Bose, A Scamardella, Brian Veitch
    Abstract:

    Tests on a systematic series of surface piercing propellers were analyzed to study some aspects of scaling the performance of this kind of propulsor. In particular, the influence of the Weber number, depth of immersion, and shaft rake are discussed and results for variations in these conditions are presented. Regression equations are given of the relationship between critical Advance Coefficient and Weber number, and of the thrust and torque Coefficients at Advance Coefficients above the critical values. This work is the result of co-operative research on the scaling of the performance of surface piercing propellers that was jointly undertaken by the University of Genoa, University of Naples, Memorial University of Newfoundland, and the Institute for Marine Dynamics, NRC.

  • Performance of dynamic azimuthing podded propulsor
    International shipbuilding progress, 2020
    Co-Authors: Ayhan Akinturk, Mohammed Islam, Brian Veitch
    Abstract:

    This paper presents results and analyses of an experimental study into the effects of static and dynamic azimuthing conditions on the propulsive characteristics of a puller podded unit in open water. The model propulsor was instrumented to measure thrust and torque of the propeller, three orthogonal forces and moments on the unit, rotational speed of the propeller, azimuthing angle and azimuthing rate. The model was first tested over a range of Advance Coefficients at various static azimuthing angles in the range of-180° to 180°. These tests were followed by tests in which the azimuthing angle was varied dynamically at certain azimuthing rate and propeller rotational speed. A comparative study of the performance Coefficients at static and dynamic azimuthing conditions in the range of-180° to 180° is presented. The performance Coefficients of the propeller and the pod unit showed a strong dependence on the propeller loading and azimuthing angle. The Coefficients in static azimuthing conditions fit well with a 10th order polynomial fit of the data obtained in the dynamic azimuthing condition in the corresponding azimuthing angles and Advance Coefficient. An uncertainty analysis of the measurements is also presented. © 2012-IOS Press and the authors.

  • Numerical investigation of propulsive characteristics of podded propellers
    2020
    Co-Authors: Islam, R Taylor, J Quinton, Neil Bose, Brian Veitch, Bruce Colbourne
    Abstract:

    Numerical investigations were performed to predict effects of propeller hub taper angle and pod geometry configurations on propulsive performance. An existing time domain panel method code was extended to handle the simulation tasks. The effect of taper angle was examined in terms of shaft thrust Coefficient, KT, and torque Coefficient, KQ, for different taper angles of -15° (pull/tractor configuration) and +15° (push configuration). The predicted pressure distribution was also analyzed to investigate the effect of taper ratio on pressure Coefficient, Cp, at the blade root section. The effects of pod-strut geometry on KT and KQ of a propeller with taper angles of 15° and 20° with two pods both in push configuration were examined. A complementary experimental study of the effects of taper angle on propulsive performance was also conducted for 15° and 20° taper angles in push configuration. Numerical predictions and experimental measurement showed a good agreement over a wide range of Advance Coefficients from the bollard pull condition to the design Advance Coefficient of about 1.0.

Hassan Ghassemi - One of the best experts on this subject based on the ideXlab platform.

  • Hydrodynamic Characteristic of the Marine Propeller in the Oblique Flow with Various Current Angle by CFD Solver
    2018
    Co-Authors: Alireza Abbasi, Hassan Ghassemi, Manouchehr Fadavie
    Abstract:

    The purpose of this study is to obtain the hydrodynamic characteristic of propeller in the oblique flow with various current angle (means oblique flow). The Reynolds-averaged Navier-Stokes (RANS) equations solver of the StarCCM+ software is employed with a realizable k-e turbulent model. In the current study, the B-Series propeller (B:4-70) is used because of its use in commercial vessels. The simulation is conducted in two parts: at first, examination of propeller behavior in direct flow conditions and comparison with experimental conditions and in the next step analysis of the propeller in the oblique flow with angles of 10, 20, 30 and 40 degrees. The results are shown that the thrust and torque Coefficients (KTx and KQx) are reduced by increasing the angle of flow and increasing the Advance Coefficient.

  • Numerical analysis of surface piercing propeller in unsteady conditions and cupped effect on ventilation pattern of blade cross-section
    Journal of Marine Science and Technology, 2016
    Co-Authors: Ehsan Yari, Hassan Ghassemi
    Abstract:

    The aim of this study is to calculate hydrodynamic performance and ventilation flow around wedge, 2D blade and 3D surface piercing propeller (SPP), using computational fluid dynamic based on Reynolds-averaged Navier–Stokes method. First, numerical analyses for two-phase fluid flow around the wedge and 2D blade section (cupped and non-cupped) are presented. Flow ventilation, pressure distribution and forces are determined and compared with experimental data. Then, the method is extended to predict the hydrodynamic performance of propeller SPP-841B. The propeller exhibits a cupped blade. In the simulated configuration, SPP is one-third submerged ( I  =  h/D  =  0.33 ) and is working at various loadings with full ventilation occurring at low Advance Coefficient ( J ). The open water performance, pressure distribution, forces/moments and ventilation pattern on the SPP-841B model are obtained and compared with experimental data. The numerical results are in good agreement with experimental measurements, especially at high Advance Coefficient.

  • Numerical simulation of turbulent flow around podded propeller in azimuthing conditions
    Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE, 2012
    Co-Authors: Reza Shamsi, Hassan Ghassemi
    Abstract:

    This paper investigates the numerical modeling of turbulent flow and hydrodynamic analysis of podded propeller in open water and azimuthing conditions. The RANS (Reynolds-Averaged Navier Stokes) based solver is used in order to study the variations of hydrodynamic characteristics of podded propeller at various angles. The variations of thrust and torque Coefficients as functions of the Advance Coefficient are obtained at various yaw angles. Turbulent flow around the propeller and pod are presented. At first, the propeller is analyzed in open water condition in absence of pod and strut. Next flow around pod and strut are simulated without effect of propellers. Finally, the whole unit is studied in zero yaw angle and azimuthing condition. These investigations are performed for two podded propulsor configurations: puller and pusher. Total forces on the unit in each direction and propeller torque are computed for a range of Advance Coefficients from 0.2 to 1. Yaw angle of pod are modified from +15° to -15° by increments of 5°. Computational results are examined against with available experimental data. Characteristic parameters including torque and thrust of propeller, axial force, and side force of unit are presented as functions of Advance Coefficient and yaw angle. The performance curves of the propeller obtained by numerical method are compared and verified by the experimental results. The results show that the propeller thrust, torque, and podded unit forces and moments in azimuthing condition depend on propeller Advance Coefficient and yaw angle. Copyright © 2012 by ASME.

Xiaoyan Wang - One of the best experts on this subject based on the ideXlab platform.

  • Characteristic analysis of unsteady viscous flow around a cavitating propeller
    Science China-technological Sciences, 2010
    Co-Authors: Shilang Fang, Xiaoyan Wang
    Abstract:

    Based on viscous multiphase flow theory, this paper presents some recent validation results with a hybrid grid and sliding mesh solving Unsteady Navier-Stokes (N-S) and Bubble Dynamics equations as applied to prediction of pressure, velocity and vapor volume fraction in the wake in an uniform inflow. Comparable to experimental results, numerical predictions of sheet cavitation, tip vortex cavitation and hub vortex cavitation are in agreement with the corresponding experimental data, the same as numerical predictions of pressure in wake. Tip vortex cavitation is the most important to generate the pressure fluctuation within the near wake. The characteristics such as blade and shaft rate frequency of propeller pressure in wake coincide with its geometric model and parameters. With increasing distance from propeller disk, the pressure signals at blade frequency decrease. The process of attenuation becomes fast with the decreased Advance Coefficient and cavitation number.

  • Characteristic analysis of unsteady viscous flow around a cavitating propeller
    Science China Technological Sciences, 2010
    Co-Authors: Zhifeng Zhu, Shilang Fang, Xiaoyan Wang
    Abstract:

    Based on viscous multiphase flow theory, this paper presents some recent validation results with a hybrid grid and sliding mesh solving Unsteady Navier-Stokes (N-S) and Bubble Dynamics equations as applied to prediction of pressure, velocity and vapor volume fraction in the wake in an uniform inflow. Comparable to experimental results, numerical predictions of sheet cavitation, tip vortex cavitation and hub vortex cavitation are in agreement with the corresponding experimental data, the same as numerical predictions of pressure in wake. Tip vortex cavitation is the most important to generate the pressure fluctuation within the near wake. The characteristics such as blade and shaft rate frequency of propeller pressure in wake coincide with its geometric model and parameters. With increasing distance from propeller disk, the pressure signals at blade frequency decrease. The process of attenuation becomes fast with the decreased Advance Coefficient and cavitation number. © 2010 Science China Press and Springer-Verlag Berlin Heidelberg.

S El Lababidy - One of the best experts on this subject based on the ideXlab platform.

  • Dynamic Positioning Thruster Near Wake Hydrodynamic Characteristics at Near Bollard Pull
    Journal of Ship Research, 2009
    Co-Authors: S El Lababidy, Neil Bose, Dan Walker
    Abstract:

    The knowledge of the hydrodynamic characteristics and momentum effects of the flow of dynamic positioning (DP) thrusters are important factors in the design of structures around the DP thrusters and in improving DP system reliability. In the present study, the flow field around a DP thruster model was precisely measured in a cavitation tunnel using a two-component laser Doppler velocimetry (LDV) system. These experiments were carried out with and without a nozzle at three different axial planes up to 1.5 diameters downstream, and the results are presented here for a pitch/diameter ratio of 1.2 at near bollard pull operating conditions (J = 0.4 and J = 0.45). This paper shows and compares the results of the DP thruster near wake hydrodynamic and momentum characteristics when operating with and without a nozzle at two different low Advance Coefficient values.

  • Detailed Analysis of the Wake of a DP Thruster Emphasizing Comparison Between LDV and SPIV Techniques
    Journal of Offshore Mechanics and Arctic Engineering-transactions of The Asme, 2005
    Co-Authors: S El Lababidy, Neil Bose, F Di Felice
    Abstract:

    To provide experimental data on the hydrodynamic characteristics and features of dynamic positioning (DP) thrusters under variable operating conditions, wake measurements were performed on a DP thruster model using 2D laser Doppler velocimetry (LDV) and stereoscopic particle image velocimetry (SPIV). These tests were performed with and without a nozzle and over a range of Advance Coefficient values including the bollard pull condition. In this paper a detailed analysis of the hydrodynamic characteristics of the wake at a plane equal to a distance of 0.5 diameters downstream from the thruster, at Advance Coefficient values of 0, 0.4, and 0.45 are presented for both the LDV and SPIV measurements showing a comparison between the results of each technique. The effect of the duct and of changes in the Advance Coefficient values is presented in this paper. Copyright © 2006 by ASME.

  • Experimental analysis of the near wake from a ducted thruster at true and near bollard pull conditions using Stereo Particle Image Velocimetry (SPIV)
    Journal of Offshore Mechanics and Arctic Engineering-transactions of The Asme, 2005
    Co-Authors: S El Lababidy, Neil Bose, Dan Walker, F Di Felice
    Abstract:

    Thrusters working at low Advance Coefficients are employed in a wide range of offshore and marine applications on Floating, Production, Storage, and Offloading (FPSO) systems; shuttle tankers; tug boats; and mobile offshore units. Therefore, an understanding of the flow around the thrusters is of great practical interest. Despite this interest, there is lack of knowledge in the description of the hydrodynamic characteristics of a ducted thruster's wake at bollard pull and low Advance Coefficient values. This work was aimed at providing detailed data about the hydrodynamic characteristics of a Dynamic Positioning (DP) thruster near wake flow at different low Advance Coefficient values. Wake measurements were made during cavitation tunnel tests carried out on a ducted propeller model at the Italian Ship Model Basin (INSEAN), Rome, Italy. Through these experiments, the DP thruster near wake velocity components at different downstream axial planes, up to 1.5 diameters downstream, were obtained using a Stereoscopic Particle Image Velocimetry (SPIV) system. These experiments were carried out at different Advance Coefficient (J) values [bollard pull (J=0), J=0.4 and J=0.45]. Copyright © 2005 by ASME.

  • Evaluation of a Dynamic Positioning Thruster Wake using Laser Doppler Velocimetry
    23rd International Conference on Offshore Mechanics and Arctic Engineering Volume 1 Parts A and B, 2004
    Co-Authors: S El Lababidy, Neil Bose
    Abstract:

    To provide information on the wake characteristics of Dynamic Positioning (DP) thrusters when operating with and without a nozzle under varied operating conditions, experiments were done on a ducted propeller model in a cavitation tunnel. The propeller flow field was measured with a two-component Laser Doppler Velocimetry (LDV) system, up to 1.5 diameters downstream. These experiments were carried out with and without the nozzle, and the results are presented here for a pitch/diameter ratio of 1.2 and an Advance Coefficient of 0.4. This paper shows and compares the results of the DP thruster near wake hydrodynamic characteristics obtained by the LDV system when operating with and without a nozzle.Copyright © 2004 by ASME