In-plane and single blade loads measurement setups for propeller performance assessment during free running and captive model tests

2020 ◽  
Vol 217 ◽  
pp. 107928
Author(s):  
Fabrizio Ortolani ◽  
Giulio Dubbioso
Keyword(s):  
Performance Assessment ◽  
Model Tests ◽  
Captive Model Tests ◽  
Free Running ◽  
Propeller Performance ◽  
Blade Loads

scholarly journals Numerical Estimation of Hull Hydrodynamic Derivatives in Ship Maneuvering Prediction

2021 ◽  
Vol 28 (2) ◽  
pp. 46-53
Author(s):  
Radosław Kołodziej ◽  
Paweł Hoffmann
Keyword(s):  
Model Tests ◽  
Circular Motion ◽  
Computational Method ◽  
Design Stage ◽  
Hydrodynamic Characteristics ◽  
Ship Maneuvering ◽  
Hydrodynamic Derivatives ◽  
Captive Model Tests ◽  
Ship Maneuverability ◽  
Free Running

Abstract Prediction of the maneuvering characteristics of a ship at the design stage can be done by means of model tests, computational simulations or a combination of both. The model tests can be realized as a direct simulation of the standard maneuvers with the free running model, which gives the most accurate results but is also the least affordable, as it requires a very large tank or natural lake, as well as the complex equipment of the model. Alternatively, a captive model test can be used to identify the hydrodynamic characteristics of the hull, which can be used to simulate the standard maneuvers with the use of dedicated software. Two types of captive model tests are distinguished: circular motion tests (CMT) and planar motion mechanism tests (PMM). The paper presents an attempt to develop a computational method for ship maneuverability prediction in which the hydrodynamic characteristics of the hull are identified by means of computational fluid dynamics (CFD). The CFD analyses presented here directly simulate the circular motion test. The resulting hull characteristics are verified against the available literature data, and the results of the simulations are verified against the results of free running model tests. Reasonable agreement shows the large potential of the proposed method.

Numerical Calculation of Added Mass for Ship Dynamic Stability by High Order Panel Method

2011 ◽  
Vol 97-98 ◽  
pp. 802-805
Author(s):  
Hua Ming Wang ◽  
Han Xing Zhao ◽  
Yu Long Yang ◽  
Xiao Song Rui
Keyword(s):  
Dynamic Stability ◽  
Three Dimensional ◽  
Added Mass ◽  
Model Tests ◽  
Panel Method ◽  
Design Stage ◽  
Captive Model Tests ◽  
Ship Maneuverability ◽  
Wigley Hull ◽  
Free Running

IMO Standards for ship maneuverability require prediction of ship’s maneuvering performance at the design stage. For this purpose, various methods such as those based on free running model tests, captive model tests or numerical simulation using mathematical models can be used. While this paper describes a numerical method for estimating ship’s dynamic stability by computing the linear sway and yaw added mass coefficients using a higher-order panel method based on Non-Uniform Rational B-Spline. Three dimensional forward-speed radiation problems are formulated and solved in frequency domain. The linear hydrodynamic coefficients are calculated and preliminary results are presented for a modified Wigley hull.

Experimental investigation of single blade loads by captive model tests in pure oblique flow

2020 ◽  
Vol 196 ◽  
pp. 106789 ◽  
Author(s):  
Fabrizio Ortolani ◽  
Michele Viviani ◽  
Giorgio Tani ◽  
Giulio Dubbioso
Keyword(s):  
Experimental Investigation ◽  
Model Tests ◽  
Oblique Flow ◽  
Captive Model Tests ◽  
Blade Loads

scholarly journals EXPERIMENTAL AND NUMERICAL INVESTIGATION ON MANEUVERING PERFORMANCE OF SMALL WATERPLANE AREA TWIN HULL

Brodogradnja ◽  
2021 ◽  
Vol 72 (2) ◽  
pp. 93-114
Author(s):  
Kun Dai ◽  
◽  
Yunbo Li ◽  
Keyword(s):  
Degrees Of Freedom ◽  
Model Tests ◽  
Navier Stokes ◽  
Modeling Group ◽  
Hydrodynamic Derivatives ◽  
Captive Model Tests ◽  
Mmg Model ◽  
Calm Water ◽  
Free Running ◽  
Convergence Study

Free running model tests and a system-based method are employed to evaluate maneuvering performance for a Small Waterplane Area Twin Hull (SWATH) ship in this paper. A 3 degrees of freedom Maneuvering Modeling Group (MMG) model is implemented to numerically simulate the maneuvering motions in calm water. Virtual captive model tests are performed by using a Reynolds-averaged Navier-Stokes (RANS) method to acquire hydrodynamic derivatives, after a convergence study to check the numerical accuracy. The turning and zigzag maneuvers are simulated by solving the maneuvering motion model and the predicted results agree well with the experimental data. Moreover, free running model tests are carried out for three lateral separations and the influence of the lateral separations on maneuvering performance is investigated. The research results of this paper will be helpful for the maneuvering prediction of the small waterplane area twin hull ship.

THE EFFECT OF LEEWAY ANGLE ON THE PROPELLER PERFORMANCE

2019 ◽  
Author(s):  
J. J. A. Schot ◽  
R Eggers
Keyword(s):  
Prediction Method ◽  
Model Tests ◽  
Design Stage ◽  
Propulsive Efficiency ◽  
Single Screw ◽  
Captive Model Tests ◽  
Twin Screw ◽  
Propeller Performance ◽  
Thrust And Torque ◽  
Ship Speed

One of the aspects influencing the performance of wind assisted vessels is the effect of leeway (drift) angle on the propeller performance. It is known that due to leeway the delivered propeller power and propulsive efficiency can vary significantly from the straight sailing condition. This effect of leeway angle is studied using a combination of viscous flow calculations and captive model tests for one twin screw and three single screw vessels. It is observed that the changes in mean axial velocity and pre-swirl rotation in the wakefield due to a combination of leeway angle and propeller suction are sufficient to describe the trends observed in captive model tests. This knowledge is used in a proposed prediction method to model the changes in propeller thrust and torque due to leeway angle at the design stage. The prediction model combined with a fit of the average wake parameters for the studied vessel types is finally used the show the trends in propulsive efficiency and delivered propeller power at constant propeller rotation rate and ship speed for small leeway angles.

Performing captive model tests with a hexapod

2019 ◽  
Vol 171 ◽  
pp. 49-58 ◽  
Author(s):  
Haiwen Tu ◽  
Lei Song ◽  
De Xie ◽  
Zeng Liu ◽  
Zhengyi Zhang ◽  
...  
Keyword(s):  
Model Tests ◽  
Captive Model Tests

Evaluation of a Small and Fast Planing Boat’s Seakeeping Performance at the Design Stage

2015 ◽  
Author(s):  
Dong Jin Kim ◽  
Sun Young Kim
Keyword(s):  
Model Tests ◽  
Full Scale ◽  
Scale Model ◽  
Design Stage ◽  
Small Scale ◽  
Irregular Wave ◽  
Seakeeping Performance ◽  
Head Waves ◽  
Scale Ratio ◽  
Free Running

Seakeeping performance of a planing boat should be sufficiently considered and evaluated at the design stage for its safe running in rough seas. Model tests in seakeeping model basins are often performed to predict the performance of full-scale planing boats. But, there are many limitations of tank size and wave maker capacity, in particular, for fast small planing boats due to small scale ratio and high Froude numbers of their scale models. In this research, scale model tests are tried in various test conditions, and results are summarized and analyzed to predict a 3 ton-class fast small planing boats designed. In a long and narrow tank, towing tests for a bare hull model are performed with regular head waves and long crested irregular head waves. Motion RAOs are derived from irregular wave tests, and they are in good agreements with RAOs in regular waves. Next, model ships with one water-jet propulsion system are built, and free running model tests are performed in ocean basins. Wave conditions such as significant heights, modal periods, and directions are varied for the free running tests. Motion RMS values, and RAOs are obtained through statistical approaches. They are compared with the results in captive tests for the bare hull model, and are used to predict the full-scale boat performances.

Development of a Multifactor Regression Model of Ship Maneuvering Forces Based on Optimized Captive-Model Tests

2006 ◽  
Vol 50 (04) ◽  
pp. 311-333 ◽  
Author(s):  
S. Sutulo ◽  
C. Guedes Soares
Keyword(s):  
Experimental Design ◽  
Polynomial Regression ◽  
Design Method ◽  
Model Tests ◽  
Ship Maneuvering ◽  
Captive Model Tests ◽  
Experimental Design Method ◽  
Force Moment ◽  
Force Components ◽  
Multifactor Regression

The paper provides the results of model tests planned with an optimized experimental design method. Captive-model tests have been carried out according to such a design on a computerized planar-motion carriage with a model of a fast catamaran with five varying factors (drift angle, rate-of-yaw amplitude, sinkage, trim and heel angles) and with all six force/moment components measured at each run. The measured values were used after preprocessing for construction of polynomial regression models for all force components acting upon the catamaran's hulls. It is demonstrated that the optimized experimental design method allows rather complicated mathematical models for maneuvering hydrodynamics forces to be obtained from captive model tests at a reasonable level of effort.

Propeller performance on a model ship in straight and steady drift motions from single blade loads and flow field measurements

2020 ◽  
Vol 197 ◽  
pp. 106881 ◽  
Author(s):  
Fabrizio Ortolani ◽  
Alessandro Capone ◽  
Giulio Dubbioso ◽  
Francisco Alves Pereira ◽  
Alessandro Maiocchi ◽  
...  
Keyword(s):  
Flow Field ◽  
Field Measurements ◽  
Propeller Performance ◽  
Blade Loads
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