A Study on Trim Optimization for a Container Ship Based on Effects due to Resistance

2016 ◽  
Vol 60 (01) ◽  
pp. 30-47
Author(s):  
Jianglong Sun ◽  
Haiwen Tu ◽  
Yongnian Chen ◽  
De Xie ◽  
Jiajian Zhou
Keyword(s):  
Container Ship ◽  
Towing Tank ◽  
Optimization Program ◽  
The Real ◽  
Computational Fluid Dynamics Cfd ◽  
Resistance Curves ◽  
Data Source ◽  
Reduce Emissions ◽  
Save Energy ◽  
Engine Power

The objective of this paper is to perform trim optimization on a 4250-TEU container ship based on the influence of trim on the resistance by using computational fluid dynamics (CFD) in conjunction with towing tank tests. First, the International Towing Tank Conference (ITTC) procedures were applied to uncertainty analysis of CFD and the CFD procedure was further verified and validated through three representative resistance curves obtained by the tests. Next, a series of resistance curves in different conditions with varied drafts and trims were obtained by the CFD computations for the model to provide data source to analyze the influence of the trim on the resistance. Results indicate that the variation of wave-making resistance due to trim dominates that of the total resistance. Finally, the resistance data for the model were converted to the engine power of the real ship. At each speed, the response surface of engine power with respect to drafts and trims was constructed and thus a trim optimization program was developed. The real ship operated under the instruction of the trim optimization program can save energy and reduce emissions significantly.

scholarly journals Trim Influence on Kriso Container Ship (KCS): An Experimental and Numerical Study

2017 ◽  
Author(s):  
Emil Shivachev ◽  
Mahdi Khorasanchi ◽  
Alexander H. Day
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Study ◽  
Computational Cost ◽  
Breaking Waves ◽  
Computational Techniques ◽  
Container Ship ◽  
Towing Tank ◽  
Operational Life ◽  
Computational Fluid Dynamics Cfd

There has been a lot of interest in trim optimisation to reduce fuel consumption and emissions of ships. Many existing ships are designed for a single operational condition with the aim of producing low resistance at their design speed and draft with an even keel. Given that a ship will often sail outside this condition over its operational life and moreover some vessels such as LNG carriers return in ballast condition in one leg, the effect of trim on ships resistance will be significant. Ship trim optimization analysis has traditionally been done through towing tank testing. Computational techniques have become increasingly popular for design and optimization applications in all engineering disciplines. Computational Fluid Dynamics (CFD), is the fastest developing area in marine fluid dynamics as an alternative to model tests. High fidelity CFD methods are capable of modelling breaking waves which is especially crucial for trim optimisation studies where the bulbous bow partially emerges or the transom stern partially immerses. This paper presents a trim optimization study on the Kriso Container Ship (KCS) using computational fluid dynamics (CFD) in conjunction with towing tank tests. A series of resistance tests for various trim angles and speeds were conducted at 1:75 scale at design draft. CFD computations were carried out for the same conditions with the hull both fixed and free to sink and trim. Dynamic sinkage and trim add to the computational cost and thus slow the optimisation process. The results obtained from CFD simulations were in good agreement with the experiments. After validating the applicability of the computational model, the same mesh, boundary conditions and solution techniques were used to obtain resistance values for different trim conditions at different Froude numbers. Both the fixed and free trim/sinkage models could predict the trend of resistance with variation of trim angles; however the fixed model failed to measure the absolute values as accurately as the free model. It was concluded that a fixed CFD model, although computationally faster and cheaper, can find the optimum trim angle but cannot predict the amount of savings with very high accuracy. Results concerning the performance of the vessel at different speeds and trim angles were analysed and optimum trim is suggested.

Reduce Emissions and Save Energy by Converting Flared Gases into Fuel Gases

2018 ◽  
Author(s):  
Venugopal Bakthavachsalam ◽  
Sevideen Abdul Shathar
Keyword(s):  
Reduce Emissions ◽  
Save Energy

scholarly journals On the Calculation of Propulsive Characteristics of a Bulk-Carrier Moving in Head Seas

2020 ◽  
Vol 8 (10) ◽  
pp. 786
Author(s):  
S. Polyzos ◽  
G. Tzabiras
Keyword(s):  
Navier Stokes ◽  
Bulk Carrier ◽  
Time Step ◽  
Towing Tank ◽  
Model Scale ◽  
Time Period ◽  
Unsteady Rans ◽  
Computational Fluid Dynamics Cfd ◽  
The Time Domain ◽  
Propeller Performance

The present work describes a simplified Computational Fluid Dynamics (CFD) approach in order to calculate the propulsive performance of a ship moving at steady forward speed in head seas. The proposed method combines experimental data concerning the added resistance at model scale with full scale Reynolds Averages Navier–Stokes (RANS) computations, using an in-house solver. In order to simulate the propeller performance, the actuator disk concept is employed. The propeller thrust is calculated in the time domain, assuming that the total resistance of the ship is the sum of the still water resistance and the added component derived by the towing tank data. The unsteady RANS equations are solved until self-propulsion is achieved at a given time step. Then, the computed values of both the flow rate through the propeller and the thrust are stored and, after the end of the examined time period, they are processed for calculating the variation of Shaft Horsepower (SHP) and RPM of the ship’s engine. The method is applied for a bulk carrier which has been tested in model scale at the towing tank of the Laboratory for Ship and Marine Hydrodynamics (LSMH) of the National Technical University of Athens (NTUA).

scholarly journals Numerical Study on Wave-Ice Interaction in the Marginal Ice Zone

2020 ◽  
Vol 9 (1) ◽  
pp. 4
Author(s):  
Tiecheng Wu ◽  
Wanzhen Luo ◽  
Dapeng Jiang ◽  
Rui Deng ◽  
Shuo Huang
Keyword(s):  
Sea Ice ◽  
Numerical Study ◽  
Test Results ◽  
Towing Tank ◽  
Marginal Ice Zone ◽  
Computational Fluid Dynamics Cfd ◽  
Numerical Research ◽  
Ice Floes ◽  
Cfd Method ◽  
Six Degree Of Freedom

The effect of waves on ice sheet is critical in the marginal ice zone (MIZ). Waves break large sea ice into small pieces and cause them to collide with each other. Simultaneously, the interaction between sea ice and waves attenuates these waves. In this study, a numerical research is conducted based on a computational fluid dynamics (CFD) method to investigate the response of single ice floe to wave action. The obtained results demonstrate that the sea ice has a violent six degree of freedom (6DoF) motion in waves. Ice floes with different sizes, thicknesses, and shapes exhibit different 6DoF motions under the action of waves. The heave and surge response amplitude operator (RAO) of the sea ice are related to wavelength. Furthermore, the overwash phenomenon can be observed in the simulation. The obtained results are compared with the model test in the towing tank based on artificial ice, and they agree well with test results.

Study on Controlling Electronic Resources System with Electronic Materials for Energy Saving

2013 ◽  
Vol 648 ◽  
pp. 344-347 ◽  
Author(s):  
Xian Zhi Tian
Keyword(s):  
Energy Saving ◽  
Electronic Materials ◽  
Electronic Resource ◽  
Real Condition ◽  
The Real ◽  
Learning Efficiency ◽  
Save Energy ◽  
Controlling Measures ◽  
Resource System ◽  
Simulation Condition

In order to improve learning efficiency and save energy, the author has studied electronic resource system for autonomous leaning with its electronic materials and energy saving system. During the study course, some electronic materials had been investigated and some users had been made real survey to get the real condition and simulation condition. Therefore, some controlling measures had been put forward and some electronic materials had been scientifically studied. The author hopes that the study will help to improve learning efficiency and saving energy.

A Study on Hovercraft Resistance Using Numerical Modeling

2016 ◽  
Vol 842 ◽  
pp. 186-190 ◽  
Author(s):  
Anh Tuan Phan
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Modeling ◽  
Research Method ◽  
Water Surface ◽  
High Speed ◽  
Flat Surfaces ◽  
The World ◽  
Computational Fluid Dynamics Cfd ◽  
Engine Power

Hovercraft operates on multi-terrains such as on water surface, on roads, on mud, on non-flat surfaces... it is used popular on the world. With the ability of operating on multi-terrains at high speed, hovercraft is used for many purposes, such as on surveying and rescues missions on areas that are not reachable by normal vehicles, on military missions and traveling... Currently, methods for estimating hovercraft resistance are not accurate enough due to many experiential formulae and coefficients involved during calculating process. This paper presents a method for calculating hovercraft resistance using computational fluid dynamics (CFD) tools. This research method is used popular and modern research method on the world. The method was applied for calculating resistance of a 7 meters length hovercraft model. The modelling results give us suggestions in selecting engine power and operating speeds for minimizing fuel consumption.

scholarly journals PERAN NADZIR DALAM PENGELOLAAN TANAH WAKAF DITINJAU DARI PERSPEKTIF UNDANG-UNDANG NOMOR 41 TAHUN 2004 (STUDI KASUS DI DESA NGADI KEC. MOJO KAB. KEDIRI)

Mahakim ◽  
2020 ◽  
Vol 4 (1) ◽  
pp. 49-63
Author(s):  
Fachrodin Fachrodin
Keyword(s):  
Field Research ◽  
The Real ◽  
Factors Influencing ◽  
Data Collecting ◽  
Research Population ◽  
Data Source ◽  
Research Type

Target in this research is: to analyze the duty nadzir in management of land ground communal ownership; To analyze the role nadzir in management of land; ground communal ownership Countryside Ngadi evaluated from in perspective Number Law 41 Year 2004; For the description of factors influencing role nadzir in management of land; ground communal. Research conducted Countryside of Ngadi of Subdistrict of Mojo of Regency Kediri. this Research Type field research. Population to be checked as above mentioned hence the sample is nadzir exist in Countryside of Ngadi Kec. Mojo Kab. Kediri. As for data source in this research, is a source of data of primary and source of data secondary. The technique of data collecting uses the interview, observation, and documentation. The result of this research is Duty nadzir in management of land; ground communal ownership Countryside of Ngadi Kec. Mojo Kab. Kediri has the duty such as those which loaded section 11 Law No 41 the Year 2004; Management communal ownership by nadzir Countryside of Ngadi Kec. maximal Uncommitted Mojo it's meaning nadzir which ought to undertake to manage and manage 12 lands; ground communal ownership in the real sharing do not at all, and land; ground communal ownership managed by one management (non nadzir).

scholarly journals CFD results on hydrodynamic performances of a marine propeller

2019 ◽  
Vol 19 (3) ◽  
pp. 345-447
Author(s):  
Luong Ngoc Loi ◽  
Nguyen Chi Cong ◽  
Ngo Van He
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Pitch Angle ◽  
Container Ship ◽  
Marine Propeller ◽  
Ansys Fluent ◽  
Characteristic Curves ◽  
Computational Fluid Dynamics Cfd ◽  
Ship Propeller ◽  
Blade Pitch Angle

In this work, the commercial Computational Fluid Dynamics (CFD), ANSYS-Fluent V.14.5 has been used to illustrate the effects of rudder and blade pitch on hydrodynamic performances of a propeller. At first, the characteristic curves of a container ship propeller are computed. Then, effects of rudder on hydrodynamic performances of the propeller in the both cases of the propeller with and without rudder have been investigated. The relationships between the blade pitch angle and the hydrodynamic performances of the selected referent propeller in this work having designed conditions as diameter of 3.65 m; speed of 200 rpm; average pitch of 2.459 m and the boss ratio of 0.1730. Using CFD, the characteristic curves of the marine propeller, pressure distribution, velocity distribution around propeller and the efficiency of the propeller have been shown. From the obtained results, the effects of rudder and blade pitch angle on hydrodynamic performances of the propeller have been evaluated.

Detailed Bow-Flow Data and CFD for a Series 60 CB = 0.6 Ship Model for Froude Number 0.316

1996 ◽  
Vol 40 (03) ◽  
pp. 193-199
Author(s):  
F. Stern ◽  
J. Longo ◽  
Z. J. Zhang ◽  
A. K. Subramani
Keyword(s):  
Thin Film ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Froude Number ◽  
Wave Profile ◽  
Flow Data ◽  
The Real ◽  
Ship Model ◽  
Wave Elevation ◽  
Computational Fluid Dynamics Cfd

The bow flow of the Series 60 CB = 0.6 ship model is reinvestigated using both experiments and computational fluid dynamics (CFD). More detailed bow-flow data are obtained by taking measurements of the wave elevation with a point gauge very near the bow. In the CFD, the bow flow is resolved in more detail by using the real bow geometry instead of the simplified vertical zero-thickness bow used in previous studies, which requires a much finer grid in the bow region. The experiments and CFD are briefly described; results are presented; and discussions are made concerning comparisons of the new and old CFD solutions with the extended data regarding the wave profile and elevation at the bow, the thin film and beads (i.e. attached spray sheet and bow vortices), and the stagnation effects.

Design and Performance Analysis of Vane Wheel

2015 ◽  
Author(s):  
Woo-Chan Seok ◽  
Hyoungsuk Lee ◽  
Tobias Zorn ◽  
Vladimir Shigunov
Keyword(s):  
Open Water ◽  
Power Reduction ◽  
Model Tests ◽  
Propulsive Efficiency ◽  
Towing Tank ◽  
Momentum Theory ◽  
Computational Fluid Dynamics Cfd ◽  
Overall Performance ◽  
And Performance ◽  
Blade Element

For the analysis, a vane wheel was considered consisting of two portions, namely, a turbine portion and a propeller portion. The turbine portion was designed using Blade Element Momentum Theory (BEMT); the propeller portion, Computational Fluid Dynamics (CFD) under open-water conditions. Model tests were conducted at Hyundai Maritime Research Institute (HMRI) in their towing tank, using a Contra Rotating Propeller (CRP) dynamometer. Model tests as well as full-scale CFD calculations were performed to predict overall performance. The CFD calculations showed better performance compared to the model tests. In general, the analyzed vane wheel improved the propulsive efficiency via power reduction compared to the case without a vane wheel.

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