Experimental Performance of a Trochoidal Propeller with High-Aspect-Ratio Blades

1989 ◽  
Vol 26 (03) ◽  
pp. 192-201 ◽  
Author(s):  
Neil Bose ◽  
Peter S. K. Lai
Keyword(s):  
Aspect Ratio ◽  
High Efficiency ◽  
Open Water ◽  
Finite Amplitude ◽  
Dynamic Stall ◽  
Frictional Drag ◽  
Overall Performance ◽  
Small Ship ◽  
Propeller Performance ◽  
Thrust And Torque

Open-water experiments were done on a model of a cycloidal-type propeller with a trochoidal blade motion. This propeller had three blades with an aspect ratio of 10. These experiments included the measurement of thrust and torque of the propeller over a range of advance ratios. Tests were done for forward and reverse operation, and at zero speed (the bollard pull condition). Results from these tests are presented and compared with: a multiple stream-tube theoretical prediction of the performance of the propeller; and a prediction of the performance of a single blade of the propeller, oscillating in heave and pitch, using unsteady small-amplitude hydrofoil theory with corrections for finite amplitude motion, finite span, and frictional drag. At present, neither of these theories gives a completely accurate prediction of propeller performance over the whole range of advance ratios, but a combination of these approaches, with an allowance for dynamic stall of the blades, should lead to a reliable simple theory for overall performance prediction. Application of a propeller of this type to a small ship is discussed. The aim of the design is to produce a lightly loaded propeller with a high efficiency of propulsion.

Numerical investigation of the rake angle effect on the hydrodynamic performance of propeller in a uniform and nonuniform flow

2019 ◽  
Vol 233 (18) ◽  
pp. 6326-6338
Author(s):  
Hasan Sajedi ◽  
Miralam Mahdi
Keyword(s):  
Open Water ◽  
Rake Angle ◽  
Uniform Flow ◽  
Wake Flow ◽  
Hydrodynamic Performance ◽  
Experimental Result ◽  
Nonuniform Flow ◽  
Solution Scheme ◽  
Propeller Performance ◽  
Thrust And Torque

Marine propeller always operates in the wake of a vehicle (ship, torpedo, submarine) but (due to the high computational cost of simulating vehicle and propeller simultaneously) to investigate the propeller geometric parameters, simulations are usually performed in open-water conditions. In this article, using the computational fluid dynamics method with the control volume approach, the effect of the rake angle on the propeller performance and formation of cavitation in the uniform flow (open water) and the nonuniform flow (wake flow) was investigated. In the nonuniform condition, the array of plates was used to simulate wake at upstream propeller. For uniform flow, steady solution scheme was adopted and for nonuniform flow unsteady solution scheme was adopted, and a moving mesh zone was generated around the propeller. To simulate cavitation a multiphase mixture flow, the Reynolds-averaged Navier–Stokes method was used and modeled by Schnerr Sauer's cavitation model. First, the E779a propeller model for numerical validation in the uniform flow and nonuniform flow was investigated. Numerical results were compared with the experimental result, and there was a good agreement between volume of the cavity, thrust, and torque coefficients. To study the effect of rake angle on the performance of B-series propellers, four models with different rake angles were modeled, and simulation was investigated behind the wake. The results of thrust, torque coefficients, and cavitation volume according to the flow parameters and cavitation number were presented as graphs. The results reveals that in the uniform flow, the rake angle has no significant effect on the propeller performance, but behind the wake flow, increase of rake causes to reduce the force applied to the propeller blades, cavitation volume, and pressure fluctuations on the propeller.

scholarly journals Prediction of Propeller Performance Using Computational Fluid Dynamics Approach

2019 ◽  
Vol 2 (2) ◽  
pp. 185-193
Author(s):  
Nur Amira Adam ◽  
Ahmad Fitriadhy ◽  
W. S. Kong ◽  
Faisal Mahmuddin ◽  
C. J. Quah
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Cfd Simulation ◽  
Computational Simulation ◽  
Open Water ◽  
Water Model ◽  
Thrust Coefficient ◽  
Propeller Performance ◽  
Prediction Approach ◽  
Thrust And Torque

A reliable prediction approach to obtain a sufficient thrust and torque to propel the ship at desired forward speed is obviously required. To achieve this objective, the authors propose to predict the thrust coefficient (KT), torque coefficient (KQ) and efficiency (η) of the propeller in open-water model test condition using Computational Fluid Dynamics (CFD) simulation approach. The computational simulation presented in the various number of rotational speed (RPM) within the range of advance ratio J=0.1 up to 1.05. The higher value of J lead to decrease 10KQ and KT. While the η increased steadily at the lower value of J and decreased at the higher value of J. The results also showed that the propeller with 1048 rpm obtain a better efficiency at J=0.95 with η= 88.25%, 10KQ=0.1654 and KT= 0.0942. The computation result is very useful as preliminary data for propeller performance characteristics.

scholarly journals Numerical Study of Hub Taper Angle on Podded Propeller Performance

2006 ◽  
Vol 43 (01) ◽  
pp. 1-10
Author(s):  
Mohammed F. Islam ◽  
Brian Veitch ◽  
Neil Bose ◽  
Pengfei Liu
Keyword(s):  
Numerical Study ◽  
Open Water ◽  
Propulsion Systems ◽  
Taper Angle ◽  
Propulsive Performance ◽  
Pressure Distributions ◽  
Overall Performance ◽  
The Difference ◽  
Propeller Blades ◽  
Propeller Performance

Presently, the majority of podded propulsion systems are of the pulling type, because this type provides better hydrodynamic efficiency than the pushing type. There are several possible explanations for the better overall performance of a puller-type podded propulsor. One is related to the difference in hub taper angle. Puller and pusher propellers have opposite hub taper angles, hence different hub and blade root shape. These differences cause changes in the flow condition and possibly influence the overall performance. The current study focuses on the variation in performance of pusher and puller propellers with the same design of blade sections, but different hub taper angles. A hyperboloidal low-order source-doublet steady/unsteady time domain panel method code, PROPELLA, was modified and used to evaluate effects of hub taper angle on the open water propulsive performance of some fixed-pitch screw propellers used in podded propulsion systems. Major findings include good agreement between predictions using the modified code and measurements, significant effects of hub taper angle on propulsive performance of tapered hub propellers, and noticeable effects of hub taper angle on sectional pressure distributions of tapered hub propeller blades.

A New Usable Propeller Series

1989 ◽  
Vol 26 (03) ◽  
pp. 173-191
Author(s):  
Stephen B. Denny ◽  
Larry T. Puckette ◽  
E. Nadine Hubble ◽  
Susan K. Smith ◽  
Richard F. Najarian
Keyword(s):  
Open Water ◽  
Fine Tuning ◽  
Second Phase ◽  
High Speeds ◽  
Engineering Department ◽  
Commercial Market ◽  
Small Craft ◽  
Pitch Ratio ◽  
Propeller Performance ◽  
Thrust And Torque

The Combatant Craft Engineering Department began, in the early 1980's, to evaluate a systematic series of propellers representing those available in the commercial market. The primary goal of the program was to generate "open-water" equivalent thrust and torque data, from full-scale trials, to improve propeller selection techniques for small craft and small ships, particularly at high speeds. The first phase of the program investigated three-bladed propellers with systematic variations in pitch ratio as well as propeller blade "cupping." Cupping has been a long-practiced, but ill-defined, art for fine-tuning propeller performance. The second phase, in 1987, expanded the series to include four-bladed propellers. In addition, the propulsion system of the test craft has been changed to achieve higher speeds, and therefore lower cavitation numbers.

Propulsion of a fin whale ( Balenoptera physalus) : why the fin whale is a fast swimmer

1989 ◽  
Vol 237 (1287) ◽  
pp. 175-200 ◽  
Keyword(s):  
Finite Amplitude ◽  
Hydrodynamic Performance ◽  
Correction Factors ◽  
Frictional Drag ◽  
Balaenoptera Physalus ◽  
Fin Whale ◽  
Hydrodynamic Efficiency ◽  
Strip Theory ◽  
Propeller Performance ◽  
Theoretical Results

Measurements of an immature fin whale {Balaenoptera physalus), which died as a result of entrapment in fishing gear near Frenchmans Cove, Newfoundland (47° 9' N, 55° 25' W), were made to obtain estimates of volume and surface area of the animal. Detailed measurements of the flukes, both planform and sections, were also obtained. A strip theory was developed to calculate the hydrodynamic performance of the whale’s flukes as an oscillating propeller. This method is based on linear, two-dimensional, small-amplitude, unsteady hydrofoil theory with correction factors used to acount for the effects of finite span and finite amplitude motion. These correction factors were developed from theoretical results of large-amplitude heaving motion and unsteady lifting-surface theory. A model that makes an estimate of the effects of viscous flow on propeller performance was superimposed on the potentialflow results. This model estimates the drag of the hydrofoil sections by assuming that the drag is similar to that of a hydrofoil section in steady flow. The performance characteristics of the flukes of the fin whale were estimated by using this method. The effects of the different correction factors, and of the frictional drag of the fluke sections, are emphasized. Frictional effects in particular were found to reduce the hydrodynamic efficiency of the flukes significantly. The results are discussed and compared with the known characteristics of fin-whale swimming.

Steady cavitating propeller performance by using OpenFOAM, StarCCM+and a boundary element method

2016 ◽  
Vol 231 (2) ◽  
pp. 411-440 ◽  
Author(s):  
Stefano Gaggero ◽  
Diego Villa
Keyword(s):  
Boundary Element Method ◽  
Open Source ◽  
Boundary Element ◽  
Open Water ◽  
Fundamental Aspect ◽  
Test Case ◽  
Numerical Predictions ◽  
Propeller Performance ◽  
Thrust And Torque ◽  
Element Method

Accurate and reliable numerical predictions of propeller performance are a fundamental aspect for any analysis and design of a modern propeller. Prediction of cavitation and of cavity extension is another important task, since cavitation is one of the crucial aspects that influences efficiency in addition to propagated noise and blade vibration and erosion. The validation of the numerical tools that support the design process, including open-source codes, is, consequently, essential. The public availability of measurements and observations which cover not only usual thrust and torque in open water conditions (including cavitation) but also unsteady functioning with pressure pulse measurements in the case of the Potsdam Propeller Test Case certainly represents an extremely useful source of information and an excellent chance for verification and validation purposes. In the present work, the prediction of the Potsdam Propeller Test Case propeller performance using the OpenFOAM computational fluid dynamics package is proposed. After a preliminary validation and calibration of the OpenFOAM native Schnerr–Sauer interphase mass transfer model for cavitating flow, based on the experimental results on a 2D NACA66Mod hydrofoil, open water propeller performance and cavitation predictions are carried out. The OpenFOAM results are finally compared both with the available experimental measurements and with calculations carried out with StarCCM+ and with a proprietary boundary element method code, in order to assess the accuracy and the overall capabilities of the open-source tools (from meshing to post-processing) available in the OpenFOAM package. The comparison, in addition to assessing the accuracy of the open-source approach, is aimed to verify its advantages and drawbacks with respect to widely used solvers and to further verify the reliability of traditional boundary element method approaches that are still widely adopted for design and optimization (thanks to their extremely higher computational efficiency) in a very demanding test case.

Gap Effect on Performance of Podded Propulsors in Straight-Ahead and Azimuthing Conditions

2010 ◽  
Vol 47 (01) ◽  
pp. 47-58
Author(s):  
Mohammed F. Islam ◽  
Brian Veitch ◽  
Pengfei Liu ◽  
Ayhan Akinturk
Keyword(s):  
Open Water ◽  
Operating Conditions ◽  
Gap Effect ◽  
Axial Distance ◽  
Noticeable Effect ◽  
Podded Propulsor ◽  
Propeller Performance ◽  
Thrust And Torque ◽  
Straight Ahead ◽  
Propeller Thrust

This paper presents results of an experimental study on the effect of gap distance on propulsive characteristics of puller and pusher podded propulsors in straight-ahead and static azimuthing open-water conditions. The gap distance is the axial distance between the rotating (propeller) and stationary (pod) parts of a podded propulsor. The propeller thrust and torque, unit forces, and moments in the three-coordinate directions of a model podded unit were measured using a custom-designed pod dynamometer in various operating conditions. The model propulsor was tested at the gap distances of 0.3%, 1%, and 2% of propeller diameter for a range of advance coefficients combined with the range of static azimuthing angles from +20_ to 20_ with a 10_ increment. The tests were conducted both in puller and pusher configurations in the same loading and azimuthing conditions. In the puller configuration, the gap distance did not have any noticeable effect on propeller torque in straight course condition, but had an effect in azimuthing conditions. The propeller thrust and efficiency were also influenced by the change of gap distance, and the effects were more pronounced at high azimuthing angles and high advance coefficients. For pusher configuration, however, the gap distance did not affect the propeller performance characteristics in straight-ahead and azimuthing conditions. Both in straight course and azimuthing conditions, the unit thrust and efficiency were not influenced by the gap distance in either puller or pusher configurations. The gap distance had a noticeable effect on unit transverse force and steering moment both in puller and pusher configurations, and both in straight course

Tail shapes lead to different propulsive mechanisms in the body/caudal fin undulation of fish

2020 ◽  
pp. 095440622096768
Author(s):  
Jialei Song ◽  
Yong Zhong ◽  
Ruxu Du ◽  
Ling Yin ◽  
Yang Ding
Keyword(s):  
Numerical Simulation ◽  
Aspect Ratio ◽  
High Efficiency ◽  
The Body ◽  
Caudal Fin ◽  
Fish Model ◽  
Swimming Efficiency ◽  
Simulation Results ◽  
Propulsive Mechanism ◽  
High Depth

In this paper, we investigate the hydrodynamics of swimmers with three caudal fins: a round one corresponding to snakehead fish ( Channidae), an indented one corresponding to saithe ( Pollachius virens), and a lunate one corresponding to tuna ( Thunnus thynnus). A direct numerical simulation (DNS) approach with a self-propelled fish model was adopted. The simulation results show that the caudal fin transitions from a pushing/suction combined propulsive mechanism to a suction-dominated propulsive mechanism with increasing aspect ratio ( AR). Interestingly, different from a previous finding that suction-based propulsion leads to high efficiency in animal swimming, this study shows that the utilization of suction-based propulsion by a high- AR caudal fin reduces swimming efficiency. Therefore, the suction-based propulsive mechanism does not necessarily lead to high efficiency, while other factors might play a role. Further analysis shows that the large lateral momentum transferred to the flow due to the high depth of the high- AR caudal fin leads to the lowest efficiency despite the most significant suction.

Recent Developments in Computational Methods for the Analysis of Ducted Propellers in Open Water

2019 ◽  
Vol 63 (4) ◽  
pp. 219-234
Author(s):  
João Baltazar ◽  
José A. C. Falcão de Campos ◽  
Johan Bosschers ◽  
Douwe Rijpkema
Keyword(s):  
Computational Methods ◽  
Open Water ◽  
Boundary Element Methods ◽  
Navier Stokes ◽  
Hydrodynamic Analysis ◽  
Numerical Predictions ◽  
Ducted Propeller ◽  
Recent Developments ◽  
Propeller Performance ◽  
Ducted Propellers

This article presents an overview of the recent developments at Instituto Superior Técnico and Maritime Research Institute Netherlands in applying computational methods for the hydrodynamic analysis of ducted propellers. The developments focus on the propeller performance prediction in open water conditions using boundary element methods and Reynolds-averaged Navier-Stokes solvers. The article starts with an estimation of the numerical errors involved in both methods. Then, the different viscous mechanisms involved in the ducted propeller flow are discussed and numerical procedures for the potential flow solution proposed. Finally, the numerical predictions are compared with experimental measurements.

Optimization of RANS Solver Simulation Setup for Propeller Open Water Performance Prediction

2015 ◽  
Author(s):  
Mohammed Islam ◽  
Fatima Jahra ◽  
Michael Doucet
Keyword(s):  
Domain Size ◽  
Open Water ◽  
Fractional Factorial ◽  
Navier Stokes ◽  
Calm Water ◽  
Simulation Results ◽  
Open Water Performance ◽  
Thrust And Torque ◽  
Simulation Time ◽  
Fixed Pitch

Mesh and domain optimization strategies for a RANS solver to accurately estimate the open water propulsive characteristics of fixed pitch propellers are proposed based on examining the effect of different mesh and computation domain parameters. The optimized mesh and domain size parameters were selected using Design of Experiments (DoE) methods enabling simulations to be carried out in a limited memory environment, and in a timely manner; without compromising the accuracy of results. A Reynolds-Averaged Navier Stokes solver is used to predict the propulsive performance of a fixed pitch propeller. The predicted thrust and torque for the propeller were compared to the corresponding measurements. A total of six meshing parameters were selected that could affect the computational results of propeller open water performance. A two-level fractional factorial design was used to screen out parameters that do not significantly contribute to explaining the dependent parameters: namely simulation time, propeller thrust and propeller torque. A total of 32 simulations were carried out only to find out that the selected six meshing parameters were significant in defining the response parameters. Optimum values of each of the input parameters were obtained for the DOE technique and additional simulations were run with those parameters. The simulation results were validated using open water experimental results of the same propeller. It was found that with the optimized meshing arrangement, the propeller opens simulation time was reduced by at least a factor of 6 as compared to the generally popular meshing arrangement. Also, the accuracy of propulsive characteristics was improved by up to 50% as compared to published simulation results. The methodologies presented in this paper can be similarly applied to other simulations such as calm water ship resistance, ship propulsion to systematically derive the optimized meshing arrangement for simulations with minimal simulation time and maximum accuracy. This investigation was carried out using STAR-CCM+, a commercial CFD package; however the findings can be applied to any RANS solver.

Sign in / Sign up

Export Citation Format

Share Document