Experimental and Numerical Investigation on the Relative Motions of an FLNG System During Side-by-Side Operation

2016 ◽  
Author(s):  
Qiaowei Xu ◽  
Zhiqiang Hu
Keyword(s):  
Numerical Calculation ◽  
Model Test ◽  
Numerical Models ◽  
Calculation Model ◽  
Test Results ◽  
Sea State ◽  
Calculation Results ◽  
Shelter Effect ◽  
Numerical Calculation Method ◽  
Relative Motions

This paper addresses a study on the relative motions of the floating liquefied natural gas (FLNG) systems during side-by-side offloading operation through experimental method and numerical calculation method. Different filling levels and sea state conditions were adopted both in model test and numerical calculation. Model test results were used to validate the numerical models, which was then used to identify the influence of the filling levels and wave/wind directions on the relative motions of the vessels. It is indicated that the numerical calculation results show satisfactory agreement with the experimental results. More severe relative motions of vessels occur when the displacement of the LNGC reduces. When the wind and wave come from the side of the LNGC, the relative sway and heave of the two vessels become more severe while the relative surge is not affected by the shelter effect. The investigation will be beneficial to the further numeral research and FLNG side-by-side offloading operation.

Experimental Study on Hydrodynamics of Hybrid Deep-V Monohull With Different Built-Up Appendages

2018 ◽  
Author(s):  
Shuzheng Sun ◽  
Hui Li ◽  
Muk Chen Ong
Keyword(s):  
Model Test ◽  
Performance Model ◽  
Hydrodynamic Performance ◽  
Irregular Waves ◽  
Hydrodynamic Characteristics ◽  
Vertical Acceleration ◽  
Test Results ◽  
Regular Waves ◽  
Sea State ◽  
Seakeeping Performance

The hydrodynamic characteristics of a hybrid deep-V monohull with different built-up appendages are investigated experimentally in order to improve the resistance and seakeeping performance. Model tests have been carried out to study the hydrodynamic performance between a bare deep-V vessel and a deep-V monohull with different built-up appendage configurations (i.e. a hybrid deep-V monohull). From the model test results, it is found that the existence of the appendages will reduce the amplitude of pitching angle and bow vertical acceleration compared to that of the bare deep-V vessel in heading regular waves. However, the resistances for the hybrid deep-V monohull with built-up appendages are increased 15.6% for Fn = 0.264, and 0.1% for Fn = 0.441 compared to the resistance of the bare deep-V vessel. The model test results of seakeeping performance in irregular waves show that the hybrid deep-V monohull gives a better seakeeping performance than the deep-V vessel. The pitching angle and bow vertical acceleration of the hybrid deep-V monohull containing a built-up appendage are reduced 15.3% and 20.6% compared to the deep-V monohull in irregular waves at Fn = 0.441 in 6th class sea state (H1/3 = 6m).

Research on Spatial Distribution and Mutual Inductance of Superconducting Pancake Coils

2012 ◽  
Vol 239-240 ◽  
pp. 305-309
Author(s):  
Fang Guo ◽  
Zhi Li
Keyword(s):  
Spatial Distribution ◽  
Numerical Calculation ◽  
Coupling Coefficient ◽  
Calculation Method ◽  
Calculation Result ◽  
Mutual Inductance ◽  
Spatial Distributions ◽  
Calculation Results ◽  
Pancake Coils ◽  
Numerical Calculation Method

This paper studies the numerical calculation method of mutual inductance between two superconducting pancake coils. And the calculation results are proved through experiment. Use this calculation method, the isoline map of two superconducting pancake coils’ coupling coefficient with the different spatial distributions is calculated. Then the designer can rapidly design the spatial distribution of superconducting pancake coils according to the coupling coefficient they needs. Specially, there is a curve of coupling coefficient equals 0 in the isoline ma. For the occasions which want to eliminate the mutual inductance between two superconducting pancake coils, this curve can provide a good guidance for design a compact layout and reduce the volume. Finally, the 0 value curve is tested under the guidance of calculation result. Through this experiment, the correctness and engineering guidance of isoline map is verified.

scholarly journals Three-Dimensional Numerical Modeling and Roof Deformation Analysis of Yuanjue Cave Based on Point Cloud Data

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Zhigang Meng ◽  
Manchao He ◽  
Zhigang Tao ◽  
Bin Li ◽  
Gang Zhao ◽  
...  
Keyword(s):  
Rock Mass ◽  
Numerical Calculation ◽  
Point Cloud ◽  
Three Dimensional ◽  
Calculation Model ◽  
Deformation Analysis ◽  
Cloud Data ◽  
Heritage Site ◽  
Calculation Results ◽  
Multifactor Coupling

Yuanjue Cave is the core exquisite cultural relic of the Dazu Stone Carvings World Cultural Heritage Site. For hundreds of years, with the continuous effect of natural forces and the erosion of various deterioration factors, the sidewall and roof rock mass of Yuanjue Cave were eroded, some parts of supporting rock mass were fragmented, and the boundary conditions of the rock mass have deteriorated, which have seriously endangered the Yuanjue Cave; once the roof collapses, the national treasure in the cave will be destroyed. In order to preevaluate the stability characteristics of the Yuanjue Cave rock mass and provide key parameters for the preventive protection of the Yuanjue Cave, this paper firstly established a refined database of key parameters of Yuanjue Cave and adjacent areas (geometry, geology, physical properties) based on three-dimensional laser point cloud scanning, a fine survey of adjacent areas, engineering geophysical prospecting, and indoor multifactor coupling tests. Then, based on FLAC3D finite difference numerical simulation technology, an accurate three-dimensional numerical calculation model of Yuanjue Cave was constructed. Finally, the model was used to analyze the roof stability of Yuanjue Cavern, revealing the deformation laws of the Yuanjue Cave roof under static load conditions, and the numerical calculation results were compared with the on-site measured results, verifying the feasibility of the high-precision modeling method, and the reliability of the numerical calculation results provided a reference for the preventive protection of the cultural relics of the cave temple.

scholarly journals Numerical calculation of the resistance of catamarans at different distances between two hulls

2021 ◽  
Vol 283 ◽  
pp. 01008
Author(s):  
Zhaochun Liu ◽  
Xiufeng Zhang ◽  
Yao Meng ◽  
Linghong Wang
Keyword(s):  
Numerical Calculation ◽  
Model Test ◽  
Calculation Method ◽  
Empirical Formula ◽  
Test Method ◽  
Hydrodynamic Characteristics ◽  
Model Parameters ◽  
Ship Model ◽  
Ship Model Test ◽  
Numerical Calculation Method

For the design of high-speed catamarans, different distances between slices have obvious interference with the total resistance of the catamaran. In order to accurately predict the hydrodynamic characteristics of the catamaran and explore the interference of the chip spacing on the resistance prediction, this paper uses a combination of CFD calculations and empirical formulas to predict the ship model resistance under different chip spacings and calculate them. The result is compared with the empirical formula. The results of the ship model test and the results calculated by the empirical formula were used to verify the numerical calculation results. The results show that the resistance change trend is consistent, and the numerical calculation method is effective and feasible. Finally, the numerical calculation method is compared with the ship model test method, and the result is within the error range, which has certain reference value for the design and optimization of the catamaran model parameters.

Calculation of the Coefficients of Ships Resistant Force in MMG Model Based on CFD

2013 ◽  
Vol 694-697 ◽  
pp. 605-613 ◽  
Author(s):  
Lin Jia Yang ◽  
Yi Han Tao
Keyword(s):  
Numerical Calculation ◽  
High Performance ◽  
Rapid Development ◽  
Resistance Coefficient ◽  
Calculation Model ◽  
Group Model ◽  
The Real ◽  
Estimation Formula ◽  
Mmg Model ◽  
Calculation Results

With the rapid development of computer, computer simulation is a reasonable way to study the maneuverability of a ship. The accuracy of ship motion mathematical model has a great effect on research results. The resistant coefficient is a crucial parameter to ship models rapidity. Hence, it is significant and practical to research how to calculate a precise resistant coefficient. This paper introduces the theoretical calculation of ship resistance coefficient and methods to get ships hydrodynamic force based on CFD theory. With the commercial CFD software Fluent, we make numerical calculation for sailing ship based on turbulence theories, and get the ships resistant coefficients of MMG (usually called Maneuvering Model Group) model. Instead of making traditional model-scale numerical calculation, we made full-scale distributed numerical calculation with high-performance computers. After comparing the calculation results with the real ships resistant coefficients, which were obtained by actual host power and ships velocity, there is a conclusion. The calculation results are very close to the real ships resistant coefficients, since the Reynolds number and the Froude number of calculation model are almost equal to those of the real ship. Computer simulations of ships circle turning were made respectively with the resistant coefficients we got and previous estimation formula of MMG model. The simulation result of calculated resistant coefficients was closer to real ships circle turning.

Theoretical Analysis on Settlement Calculation of Pile Foundation with Minimum Complementary Energy of Elastic Mechanics Based on the Ritz Variational Method

2013 ◽  
Vol 788 ◽  
pp. 636-639
Author(s):  
Zhi Ran Yao ◽  
Xin Sheng Ge
Keyword(s):  
Variational Method ◽  
Theoretical Calculation ◽  
Model Test ◽  
Pile Group ◽  
Test Results ◽  
Complementary Energy ◽  
Settlement Calculation ◽  
Calculation Results ◽  
Elastic Mechanics ◽  
Matlab Programming

In this paper, based on the model test，numerous deductions and calculations have been done, which was about the settlement of single pile and pile group in homogeneous foundation. With minimum complementary energy of elastic mechanics on the basis of the ritz variational method, through the MATLAB programming, theoretical calculation results were obtained, then comparison and analysis with the model test results were made to verify the feasibility of theoretical calculation.

Influence of Polymer Material on the Sensitivity of Packaged Fiber Bragg Grating

2010 ◽  
Vol 663-665 ◽  
pp. 930-933
Author(s):  
Zhi Zhong Li ◽  
Rong Guang Sun ◽  
Qi Jun Liu ◽  
Yi Chuan Wang
Keyword(s):  
Thermal Expansion ◽  
Numerical Calculation ◽  
Young’S Modulus ◽  
Polymer Material ◽  
Young's Modulus ◽  
Pressure Sensitivity ◽  
Calculation Results ◽  
High Thermal Expansion ◽  
Numerical Calculation Method ◽  
High Thermal Expansion Coefficient

Numerical calculation method is adopted to analyze to the influence of the polymer material on the sensitivity of coated FBG. The calculation results show that, the polymer material with high Young's modulus and high thermal expansion coefficient helps to improve the temperature sensitivity of the coated FBG; and the material with low Young's modulus and low Poisson's ratio helps to improve the pressure sensitivity. The polymer-coated FBG experiment is explored, in which the pressure and temperature sensitivities are enhanced 12-fold and 7-fold respectively.

scholarly journals The Deformation Characteristics of Weak Foundation with High Back Siltation in the Immersed Tunnel

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Xiabing Yue ◽  
Yuan Xie ◽  
Yongli Xie
Keyword(s):  
Numerical Calculation ◽  
Model Test ◽  
Calculation Method ◽  
Centrifuge Model Test ◽  
Deformation Characteristics ◽  
Test Results ◽  
Centrifuge Model ◽  
Immersed Tunnel ◽  
Natural Foundation ◽  
Tube Structure

The deformation characteristics of a weak foundation with high back siltation in an immersed tunnel lack empirical data; however, the calculation method and control of foundation settlements are highly important to tunnel design and construction. This paper takes a cross section of the natural foundation of an immersed tunnel in the Hong Kong-Zhuhai-Macao Bridge (HZMB) as the research object and conducts a centrifuge model test. The soil layer is divided, and the soil parameters are determined by the CPTU and the indoor dynamic three triaxial test. In consideration of the actual engineering scale and the ability of the centrifuge model test system, the similarity ratio of the model to the prototype is studied and determined. As for the immersed tube structure, the deformation characteristics are mainly studied. Therefore, the organic glass is selected as the model material by the similarity of the elastic modulus and the density. The characteristics of the resilience and recompression of the natural foundation of the immersed tunnel and the strain characteristics of the immersed tube structure are obtained by the analysis of the multiworking condition test data. Moreover, based on the actual engineering geological conditions of the subsea tunnel, a numerical calculation method is carried out to check the reliability of the centrifuge model test results. The results of the numerical calculation are consistent with the model test results.

Float Over Installation Method—Comprehensive Comparison Between Numerical and Model Test Results

2006 ◽  
Vol 128 (3) ◽  
pp. 256-262 ◽  
Author(s):  
Arcandra Tahar ◽  
John Halkyard ◽  
Atle Steen ◽  
Lyle Finn
Keyword(s):  
West Africa ◽  
Gulf Of Mexico ◽  
Model Test ◽  
Test Results ◽  
Sea State ◽  
Numerical Predictions ◽  
Single Piece ◽  
Heavy Lift ◽  
Compliant Tower ◽  
Comprehensive Comparison

Installing a large deck onto a platform, such as a spar, using the floatover method is gaining popularity. This is because the operational cost is much lower than other methods of installation, such as modular lifts or a single piece installation by a heavy lift barge. Deck integration can be performed on land, at quay side and will not depend on a heavy lift barge. A new concept for a floatover vessel has been developed for operations in the Gulf of Mexico and West Africa. In this application sea state conditions are essential factors that must be considered in the Gulf of Mexico, especially for transportation. In West Africa, swell conditions will govern floatover deck (FOD) installation. Based on these two different environmental conditions, Technip Offshore, Inc. developed the FOD installation concept using semi-submersible barge type vessels. A significant amount of development work and model testing has been done on this method in recent years on spar floatover. These tests have validated our numerical methods. Another test was conducted to investigate the feasibility of a deck float-over operation onto a compliant tower for a West Africa project. The project consists of a compliant tower supporting a 25,401metricton(28,000s.ton) integrated deck. This paper will describe comparisons between model test data and numerical predictions of the compliant tower floatover operation.

Algorithm and Experiment of the Separated Foundation Bearing Capacity of Culverts Considering Lateral Fill

2012 ◽  
Vol 450-451 ◽  
pp. 1616-1624
Author(s):  
Wen Lu Wang ◽  
Shu Jun Cui ◽  
Da Jun Zhao ◽  
Lei Wang
Keyword(s):  
Bearing Capacity ◽  
Model Test ◽  
Similarity Theory ◽  
Calculation Model ◽  
Test Results ◽  
Foundation Soil ◽  
Model Experiments ◽  
M 10 ◽  
Foundation Deformation ◽  
M 12

How to determine the foundation bearing capacity of high-stacked culverts in highway construction becomes a problem that must be taken seriously. Combining with the stress characteristics of the foundation soil, the soil force was analyzed for finding the improved effect on the separated foundation bearing capacity of lateral fill. Establishing the calculation model and algorithm, the general formulation of separated foundation bearing capacity considering lateral fill was deduced. Then under direction of similarity theory, six model experiments were designed to simulate the silt clay foundation deformation in whole loading process. The pressure-settlement curves were drew and the foundation bearing capacity under lateral fill height of 0 m, 4 m, 6 m, 8 m, 10 m, 12 m were measured. Test results showed that with the fill height increasing the bearing capacity increased significantly, it had been reached 815 kPa when the fill height was 10 m. But the growth was nonlinear, it first increased from 18.40% to 20.37% and then reduced to 8.59%. At last the bearing capacity reached 885 kPa while fill height exceeded 12 m. Meanwhile the errors between the calculated results and measured by model test were almost less than 10% so the algorithm was feasible. The conclusion is that the lateral fill is advantageous for improve the foundation bearing capacity and reduce project cost significantly when the settlement of the culverts foundation satisfied the design request, with the lateral fill increasing, the rate of the improvement first increases and then decreases, at last it tends to 885 KPa when fill height exceeded 12 m.

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