Maneuvering Prediction of a VLCC Model Based on CFD Simulation for PMM Tests by Using a Circulating Water Channel

Author(s):  
Han Liu ◽  
Ning Ma ◽  
Xiechong Gu

Since ship maneuverability is a vitally important characteristic of ship design, several experimental techniques to determine ship maneuverability are recommended, among which using the planar motion mechanism (PMM) test for captive model in a circulating water channel (CWC) has become a new and effective way for captive model tests. This paper uses the numerical method to study the viscous hydrodynamic forces acting on a KVLCC2 model. The viscous flow around the model and its hydrodynamic forces in the oblique towing, pure sway and pure yaw test are simulated by CFD, in which the steady and unsteady RANS equations in conjunction with a RNG k-ε turbulence model are solved. By applying the dynamic mesh technique, the motion of pure sway is simulated. As a key technique for realization of pure yaw motion a new method combining the layering and local remeshing that treats restricted water region problem like in a CWC is developed. Accuracy of the proposed numerical method is confirmed by comparing the calculated hydrodynamic forces with the measured one. Then hydrodynamic derivatives of ship maneuvering movements are analyzed, and used in maneuvering prediction which is based on MMG model for turning test. Results show that the hybrid dynamic mesh technique is a practically efficient way to simulation of the pure yaw motion in CWC, which balances computational accuracy and efficiency. It also demonstrates that the present numerical model gives satisfactory results on PMM tests and maneuvering motions in terms of accuracy and it can be an economical method for engineering practices.

2021 ◽  
Author(s):  
Chengqian Ma ◽  
Ning Ma ◽  
Xiechong Gu

Abstract The benchmark experiment research for the maneuverability of a small-scaled ship model is critical for investigating the scaled effect on the maneuvering hydrodynamic derivatives, and validating the CFD technology. Till now, there is little research on the benchmark study and uncertainty analysis for the small-scaled ship which is frequently used in the Circulating Water Channel (CWC). Therefore, an experimental study of the planar motion mechanism (PMM) tests is performed in the CWC of the SJTU. The PMM tests performed in the CWC can avoid some disadvantages of those in the towing tank, such as the limitations on the acquisition time and frequency due to the size of the towing tank, interference of the carriage on the signal acquisition. In addition, the flow field visualization for the tests in the CWC is easier to achieve compared with the experiments in the towing tank, which helps the scholars to understand the characteristic of the wake field during maneuvers. The benchmark ship is the KVLCC2 with a scaled ratio of 1/128.77. The hull forces are recorded and processed to obtain the maneuvering hydrodynamic derivatives. To assess the quality of the acquired data, randomness analysis, stationarity analysis, normality analysis, and statistical convergence are performed for the PMM tests in the CWC for the first time. Finally, the uncertainty analysis (UA) method for the PMM tests performed in the CWC is also developed.


2021 ◽  
Vol 28 (2) ◽  
pp. 46-53
Author(s):  
Radosław Kołodziej ◽  
Paweł Hoffmann

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.


Fuel ◽  
2020 ◽  
Vol 259 ◽  
pp. 116083 ◽  
Author(s):  
Zhimin Zheng ◽  
Wenming Yang ◽  
Peng Yu ◽  
Yongtie Cai ◽  
Hao Zhou ◽  
...  

2013 ◽  
Vol 791-793 ◽  
pp. 1069-1072 ◽  
Author(s):  
Shao Zhu Wang ◽  
Han Ping Wang ◽  
Ming Yang ◽  
Lin Peng Wang ◽  
Guang Wei Wei

Cool Launch project is an important launch mode of submarine launched missile, the water-exit trajectory characteristic of the missile in launching process becomes to research focus. Model of three dimensional water-exit trajectory of submarine launched missile was built based on dynamic mesh technique and simulation operation was carried out to obtain the characteristics of water-exit trajectory & attitude. The method adopted in the establishment of the model and the result has provided references to the research of water-exit trajectory.


2017 ◽  
Vol 170 ◽  
pp. 139-153 ◽  
Author(s):  
Swapnil V. Ghatage ◽  
Md. Shakhaoath Khan ◽  
Zhengbiao Peng ◽  
Elham Doroodchi ◽  
Behdad Moghtaderi ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document