Developing Innovative Deep Water Pipeline Construction Techniques with Physical Models

2004 ◽  
Vol 129 (1) ◽  
pp. 56-60 ◽  
Author(s):  
R. J. Brown ◽  
Andrew Palmer
Keyword(s):  
Deep Water ◽  
Large Scale ◽  
Three Dimensional ◽  
Physical Models ◽  
Governing Equations ◽  
Pipeline Construction ◽  
Construction Techniques ◽  
Construction Risk ◽  
Water Pipeline ◽  
Model Technique

On the large scale of deep-water construction, marine pipelines are extremely flexible. Construction procedures can exploit that flexibility to connect pipelines and risers to floaters, manifolds, wellheads, buoys, and platforms. The paper describes a three-dimensional physical model technique. It helps the engineer to think imaginatively and rapidly to explore different options, with the objective of minimizing construction risk and creating procedures that can be accomplished by the equipment available. The relevant governing equations are derived, and from them come the conditions required for the model to obey the correct mechanical similarity conditions. The model is exact, and can be used to derive forces and stresses; it is much more than just a picture. The paper describes a series of applications to two- and three-dimensional pipeline construction problems, most recently an application to the current Thunder Horse project.

scholarly journals NUMERICAL SIMULATION OF THREE-DIMENSIONAL FLOW AROUND HARBOR DUE TO TSUNAMI USING FAVOR METHOD AND WENO SCHEME

2018 ◽  
pp. 71
Author(s):  
Yuki Kajikawa ◽  
Masamitsu Kuroiwa ◽  
Naohiro Otani
Keyword(s):  
Flow Field ◽  
Large Scale ◽  
Three Dimensional ◽  
Weno Scheme ◽  
Scale Model ◽  
Governing Equations ◽  
3D Flow ◽  
Complex Boundaries ◽  
Cartesian Coordinate ◽  
Fifth Order

In this paper, a three-dimensional (3D) tsunami flow model was proposed in order to predict a 3D flow field around a harbor accurately when tsunami strikes. In the proposed numerical model, the Cartesian coordinate system was adopted, and the Fractional Area/Volume Obstacle Representation (FAVOR) method, which has the ability to impose boundary conditions smoothly at complex boundaries, was introduced into the governing equations in consideration of applying the estimation to actual harbors with complex shape in the future. Moreover, the fifth-order Weighted Essentially Non- Oscillatory (WENO) scheme, which is a technique for achieving high accuracy even if the calculation mesh is coarse, was applied to discretization of the convection terms of the governing equations. In order to verify the validity of the model, it was applied to a large-scale laboratory experiment with a scale model of harbor. Comparisons between the simulated and experimental results showed that the model was able to reproduce the time variation of the flow field with sufficient accuracy. Moreover, the simulated results showed that a complex 3D flow field with some vertical vortex flows was generated around a harbor when tsunami struck.

The Model Test of Deep Water S-Lay Stinger Using Dynamical Substructure Method

2015 ◽  
Vol 137 (1) ◽  
Author(s):  
Xiangfeng Zhang ◽  
Qianjin Yue ◽  
Wenshou Zhang
Keyword(s):  
Model Test ◽  
Deep Water ◽  
Large Scale ◽  
Test Method ◽  
Scale Model ◽  
Length Scale ◽  
Model Structure ◽  
Large Scale Model ◽  
Test Platform ◽  
Water Pipeline

Deep water pipeline installations by S-lay present many challenges, especially in the overbend section. The S-lay requires a long curved and stiff stinger to support the pipeline weight. The interaction between the overbend pipe and stinger is complicated such that the numerical structure analysis could not sufficiently predict the mechanical behavior of the installing process. A dynamic substructure model test method with 1:20 length scale for 2000 m water depth is addressed in this paper, where the large scale model structure can be tested to simulate the vessel movements during installation. The roller forces influenced by the stinger stiffness and vessel movements are discussed based on the test platform.

Research on Algorithm of Gauss Curvature on Space Mesh Points of Battlefield Large-Scale Terrain and its Visualization

2014 ◽  
Vol 543-547 ◽  
pp. 1803-1806
Author(s):  
Shi Bin Liu ◽  
Cheng Wang ◽  
Yan Ping Yang ◽  
Xing Yan Liu
Keyword(s):  
Error Analysis ◽  
Large Scale ◽  
Three Dimensional ◽  
Gauss Curvature ◽  
Good Effect ◽  
Full Detail ◽  
C Language ◽  
Terrain Model ◽  
Fast Speed ◽  
Model Technique

This paper discusses the calculation method of Gauss Curvature on space mesh points in simplified level-of-detail (LOD) model technique and how to program with C# language at the platform of .NET. Then, with this algorithm, get the curvature value of the mesh points, delete the center point of the small curvature and triangularize the cavity left so as to realize the simplification of the LOD model. In order to show the result of this algorithm, this paper visualizes the LOD model of the three-dimensional terrain model in full detail with Gauss Curvature Algorithm, puts forward the idea of carrying out error analysis on the algorithm with the geometric property of curvature, and compares the result with that with other algorithms. All the example and the error analysis show that this algorithm is not only of fast speed but also with good effect.

A Method for Three-Dimensional Navier–Stokes Simulations of Large-Scale Regions of the Human Lung Airway

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
D. Keith Walters ◽  
William H. Luke
Keyword(s):  
Large Scale ◽  
Cfd Simulation ◽  
Computational Cost ◽  
Three Dimensional ◽  
Mesh Size ◽  
Flow Path ◽  
Physical Models ◽  
Navier Stokes ◽  
Small Scale ◽  
Flow Geometry

A new methodology for CFD simulation of airflow in the human bronchopulmonary tree is presented. The new approach provides a means for detailed resolution of the flow features via three-dimensional Navier–Stokes CFD simulation without the need for full resolution of the entire flow geometry, which is well beyond the reach of available computing power now and in the foreseeable future. The method is based on a finite number of flow paths, each of which is fully resolved, to provide a detailed description of the entire complex small-scale flowfield. A stochastic coupling approach is used for the unresolved flow path boundary conditions, yielding a virtual flow geometry that allows accurate statistical resolution of the flow at all scales for any set of flow conditions. Results are presented for multigenerational lung models based on the Weibel morphology and the anatomical data of Hammersley and Olson (1992, “Physical Models of the Smaller Pulmonary Airways,” J. Appl. Physiol., 72(6), pp. 2402–2414). Validation simulations are performed for a portion of the bronchiole region (generations 4–12) using the flow path ensemble method, and compared with simulations that are geometrically fully resolved. Results are obtained for three inspiratory flowrates and compared in terms of pressure drop, flow distribution characteristics, and flow structure. Results show excellent agreement with the fully resolved geometry, while reducing the mesh size and computational cost by up to an order of magnitude.

Baroclinic instability of large-amplitude geostrophic flows

1993 ◽  
Vol 251 ◽  
pp. 501-514 ◽  
Author(s):  
E. S. Benilov
Keyword(s):  
Large Amplitude ◽  
Large Scale ◽  
Hamiltonian Structure ◽  
Baroclinic Instability ◽  
Three Dimensional ◽  
Vertical Shear ◽  
Governing Equations ◽  
Zonal Flows ◽  
Wave Disturbances ◽  
Geostrophic Flows

This paper examines the large-scale dynamics of a layer of stratified fluid on the β-plane. A three-dimensional asymptotic system is derived which governs geostrophic flows with large displacement of isopycnal surfaces. This is then reduced to a two-dimensional set of equations which describe the interaction of a baroclinic ‘quasi-mode’ with arbitrary vertical profile and barotrophic motion. The baroclinic instability of large-amplitude zonal flows with vertical shear is studied within the framework of these equations. In the case where the displacement of isopycnal surfaces is small, the results obtained should overlap with the ‘traditional’ baroclinic instability of quasi-geostrophic (small-amplitude) flows. In order to compare the two types of instability, the quasi-geostrophic boundary-value problem is solved asymptotically for the case of long-wave disturbances and weak β-effect (the latter limit of quasi-geostrophic theory has not been considered previously). The instability that is found is linked to the Hamiltonian structure of the governing equations. The equations derived are generalized for the case of more than one baroclinic quasi-mode.

scholarly journals Hi-C-constrained physical models of human chromosomes recover functionally-related properties of genome organization

2016 ◽  
Author(s):  
Marco Di Stefano ◽  
Jonas Paulsen ◽  
Tonje G. Lien ◽  
Eivind Hovig ◽  
Cristian Micheletti
Keyword(s):  
Data Analysis ◽  
Genome Organization ◽  
Large Scale ◽  
Three Dimensional ◽  
Active Regions ◽  
Physical Modelling ◽  
Physical Models ◽  
Contact Data ◽  
Functional Features

ABSTRACTCombining genome-wide structural models with phenomenological data is at the forefront of efforts to understand the organizational principles regulating the human genome. Here, we use chromosome-chromosome contact data as knowledge- based constraints for large-scale three-dimensional models of the human diploid genome. The resulting models remain minimally entangled and acquire several functional features that are observed in vivo and that were never used as input for the model. We find, for instance, that gene-rich, active regions are drawn towards the nuclear center, while gene poor and lamina-associated domains are pushed to the periphery. These and other properties persist upon adding local contact constraints, suggesting their compatibility with non-local constraints for the genome organization. The results show that suitable combinations of data analysis and physical modelling can expose the unexpectedly rich functionally-related properties implicit in chromosome-chromosome contact data. Specific directions are suggested for further developments based on combining experimental data analysis and genomic structural modelling.

Propagation and Reflection of Plane Waves in a Rotating Magneto-Elastic Fibre-Reinforced Semi Space with Surface Stress

2020 ◽  
Vol 22 (4) ◽  
pp. 939-958
Author(s):  
Indrajit Roy ◽  
D. P. Acharya ◽  
Sourav Acharya
Keyword(s):  
Surface Stress ◽  
Incident Angle ◽  
Plane Waves ◽  
Three Dimensional ◽  
Elastic Fibre ◽  
Amplitude Ratios ◽  
Governing Equations ◽  
Rotation Surface ◽  
Wave Velocities ◽  
Magnetic Field Rotation

AbstractThe present paper investigates the propagation of quasi longitudinal (qLD) and quasi transverse (qTD) waves in a magneto elastic fibre-reinforced rotating semi-infinite medium. Reflections of waves from the flat boundary with surface stress have been studied in details. The governing equations have been used to obtain the polynomial characteristic equation from which qLD and qTD wave velocities are found. It is observed that both the wave velocities depend upon the incident angle. After imposing the appropriate boundary conditions including surface stress the resultant amplitude ratios for the total displacements have been obtained. Numerically simulated results have been depicted graphically by displaying two and three dimensional graphs to highlight the influence of magnetic field, rotation, surface stress and fibre-reinforcing nature of the material medium on the propagation and reflection of plane waves.

scholarly journals A Review on Additive Manufacturing Possibilities for Electrical Machines

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1940
Author(s):  
Muhammad Usman Naseer ◽  
Ants Kallaste ◽  
Bilal Asad ◽  
Toomas Vaimann ◽  
Anton Rassõlkin
Keyword(s):  
Additive Manufacturing ◽  
Large Scale ◽  
Three Dimensional ◽  
Electrical Machines ◽  
Electromagnetic Properties ◽  
Scale Production ◽  
Performance Parameters ◽  
Large Scale Production ◽  
One Step ◽  
Manufacturing Techniques

This paper presents current research trends and prospects of utilizing additive manufacturing (AM) techniques to manufacture electrical machines. Modern-day machine applications require extraordinary performance parameters such as high power-density, integrated functionalities, improved thermal, mechanical & electromagnetic properties. AM offers a higher degree of design flexibility to achieve these performance parameters, which is impossible to realize through conventional manufacturing techniques. AM has a lot to offer in every aspect of machine fabrication, such that from size/weight reduction to the realization of complex geometric designs. However, some practical limitations of existing AM techniques restrict their utilization in large scale production industry. The introduction of three-dimensional asymmetry in machine design is an aspect that can be exploited most with the prevalent level of research in AM. In order to take one step further towards the enablement of large-scale production of AM-built electrical machines, this paper also discusses some machine types which can best utilize existing developments in the field of AM.

scholarly journals Vibration characteristics of triple-gear-rotor system in compressed air energy storage under variable torque load

2021 ◽  
Vol 104 (1) ◽  
pp. 003685042098705
Author(s):  
Xinran Wang ◽  
Yangli Zhu ◽  
Wen Li ◽  
Dongxu Hu ◽  
Xuehui Zhang ◽  
...  
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Element Model ◽  
Rotor System ◽  
Dynamic Responses ◽  
System Response ◽  
Rotating Speed ◽  
Torque Load ◽  
Set Up ◽  
Two Stages

This paper focuses on the effects of the off-design operation of CAES on the dynamic characteristics of the triple-gear-rotor system. A finite element model of the system is set up with unbalanced excitations, torque load excitations, and backlash which lead to variations of tooth contact status. An experiment is carried out to verify the accuracy of the mathematical model. The results show that when the system is subjected to large-scale torque load lifting at a high rotating speed, it has two stages of relatively strong periodicity when the torque load is light, and of chaotic when the torque load is heavy, with the transition between the two states being relatively quick and violent. The analysis of the three-dimensional acceleration spectrum and the meshing force shows that the variation in the meshing state and the fluctuation of the meshing force is the basic reasons for the variation in the system response with the torque load. In addition, the three rotors in the triple-gear-rotor system studied show a strong similarity in the meshing states and meshing force fluctuations, which result in the similarity in the dynamic responses of the three rotors.

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