Strake Design and VIM-Suppression Study of a Cell-Truss Spar

2010 ◽  
Author(s):  
Ying Wang ◽  
Jianmin Yang ◽  
Tao Peng ◽  
Haining Lu
Keyword(s):  
Oil And Gas ◽  
Hydrodynamic Performance ◽  
Design Stage ◽  
Concept Design ◽  
Ocean Engineering ◽  
Design And Optimization ◽  
Fluid Field ◽  
Spar Platforms ◽  
Helical Strakes ◽  
Truss Spar

Along with the development of offshore technology, Spar platforms have been widely used in deep-sea oil and gas exploitation. Due to the deep draft cylinder hull piercing into the water, Spar platforms could be subjected to Vortex-Induced Motions (VIM) in certain current conditions. To mitigate VIM, helical strakes are used on the Spar hulls, and they have been proved to be effective. Cell-Truss Spar is a new concept of Spar platform which has recently been put forward by State Key Laboratory of Ocean Engineering (SKLOE) of Shanghai Jiao Tong University. It combines some good qualities of the Cell Spar and Truss Spar designs, aiming to bring in the lighter truss section and heave plate damping feature of the Truss Spar to obtain satisfactory heave motion performances, while reduce manufacture and installation difficulties by means of cell concept. Since the Cell-Truss Spar is a new design concept that has physical characteristics which are different from the existing Spars, the global motion performance should be carefully studied and verified. Researches about the VIM performance of the Cell-Truss Spar have been carried out recently (see Wang Ying et al, 2008, etc). Since it is still at the concept design stage, the Cell-Truss Spar configuration is considered without detail strake design in these studies. For the Cell-Truss Spar, which is still on concept design stage at the present time, the design and optimization of the helical strakes is very important to control the VIM response and improve the hydrodynamic performance. In this paper, strake design and VIM-Suppression Study of the Cell-Truss Spar is carried out. As a result of the unique characters on the hull, the outer surface of the Cell-Truss Spar does not form a regular cylinder. Hence, the strakes should be designed more carefully. In this study, four different configurations of strake groups are put forward and studied, and the one with the highest efficiency is chosen to be applied on the Cell-Truss Spar. The fluid field around the hard tank of the hull, the vortex disturbance near the strakes, and the forces acting on the hard tank with different strakes are simulated by CFD method, and the strake efficiency is assessed through model test combining with CFD computation. The optimized strake configuration is finally chosen, and the VIM performance of the strake-equipped Spar is studied.

Experimental Study on Wet Tow and Upending of a Truss Spar

2011 ◽  
Author(s):  
Lin Liu ◽  
Longfei Xiao ◽  
Zhiqiang Hu ◽  
Lijun Yang
Keyword(s):  
Experimental Study ◽  
Oil And Gas ◽  
Research Work ◽  
Hydrodynamic Characteristics ◽  
Test Results ◽  
Ocean Engineering ◽  
Spar Platform ◽  
Key Points ◽  
Truss Spar ◽  
Global Moment

In recent years, with the development of the deepwater oil and gas exploitation, the Spar platform has received more and more attention. A lot of research work has been done on the Spar platform, but experimental study on the process of wet tow and upending of Truss Spar is seldom conducted. Recently, a wet tow and upending model test of a Truss Spar was carried out in the State Key Laboratory of Ocean Engineering in Shanghai Jiao Tong University. The hydrodynamic characteristics and the global loads on the key points of the Truss Spar during the period of wet tow and upending are focused on. In the wet tow tests, the tow resistance, 6DOF motions, global loads and the relative wave elevations are measured and analyzed. During the upending simulation, the measuring parameters consist of the motions and the global moment at the connection points between the hard tank and the truss. The test program and test results are presented and discussed in this paper offering the value references for the wet tow and upending operation in reality of the Truss Spar.

CFD Analysis of Unsteady Flows Around a New Cell-Truss Spar and the Corresponding Vortex-Induced Motions

2008 ◽  
Author(s):  
Ying Wang ◽  
Jianmin Yang ◽  
Xin Li
Keyword(s):  
Fluid Dynamic ◽  
Unsteady Flows ◽  
3D Simulation ◽  
Nonlinear Flow ◽  
Design Stage ◽  
Experimental Investigations ◽  
Ocean Engineering ◽  
2D Simulation ◽  
Hexahedral Elements ◽  
Truss Spar

A new configuration of Spar platform called the Cell-Truss Spar has recently been put forward by State Key Laboratory of Ocean Engineering (SKLOE) of Shanghai Jiao Tong University. Since the Cell-Truss Spar is a new design concept that has several physical characteristics which are different from those of the present Classic, Truss and Cell Spars, many aspects of its performances in various sea conditions should be carefully studied. For any type of Spars, Vortex-Induced Motions (VIM) under current flow is an important consideration since it not only affects the motion performance of the Spar, but also reacts on the fatigue analysis and Spar mooring design. This paper mainly discusses the unsteady flows around the new Cell-Truss Spar and the corresponding vortex-induced motion performances of the Spar in uniform currents. A CFD model of the Cell-Truss Spar upper hull (without strake designs for VIM mitigation since it’s still at the concept design stage at the present time) with a scale ratio of 1:100 is created and numerical simulations at different current conditions are performed. The software FLUENT is chosen as the computational fluid dynamic tool to simulate the flow fields around the Cell-Truss Spar and the resulting vortex-induced motions. Both 2D and 3D simulations are carried out. Dynamic meshes and user defined functions are used in the fluid-structure interaction for solving the equations of motion. The SST k-ω method is used as the turbulence model in the 2D simulation and the Detached Eddy Simulation (DES) is used in the 3D simulation. In the 2D simulation, the unsteady flows around the Cell-Truss Spar hard tank at different Reynolds numbers are calculated and the corresponding vortex shedding features and other fluid parameters are obtained and analyzed. Moreover, in order to set up a baseline for the comparison and analysis of the Cell-Truss Spar, a typical Truss Spar hard tank with the same diameter and draft is also modeled and calculated. Comparisons with several classical experimental and numerical results are conducted to validate the numerical method. The Cell-Truss Spar hull VIM responses are then simulated. For the 3D simulation, the fluid domain is made of a hybrid mesh comprising of millions of wedgy and hexahedral elements. Since 3D simulation is very time-consuming, only the results of the nonlinear flow field features for the currents passing the stationary Spar are presented in this paper, and more advanced studies related to this subject including both numerical and experimental investigations would be carried out successively.

scholarly journals SIMULTANEOUS DEFINITION OF KEY CHARACTERISTICS IN ORDER TO FACILITATE ROBUST DESIGN IN EARLY PRODUCT DEVELOPMENT STAGES

2021 ◽  
Vol 1 ◽  
pp. 2691-2700
Author(s):  
Stefan Goetz ◽  
Dennis Horber ◽  
Benjamin Schleich ◽  
Sandro Wartzack
Keyword(s):  
Product Development ◽  
Robust Design ◽  
Language Processing ◽  
Design Stage ◽  
Concept Design ◽  
Clear Definition ◽  
Implicit Information ◽  
Key Characteristics ◽  
Associated Functions ◽  
Definition Of

AbstractThe success of complex product development projects strongly depends on the clear definition of target factors that allow a reliable statement about the fulfilment of the product requirements. In the context of tolerancing and robust design, Key Characteristics (KCs) have been established for this purpose and form the basis for all downstream activities. In order to integrate the activities related to the KC definition into product development as early as possible, the often vaguely formulated requirements must be translated into quantifiable KCs. However, this is primarily a manual process, so the results strongly depend on the experience of the design engineer.In order to overcome this problem, a novel computer-aided approach is presented, which automatically derives associated functions and KCs already during the definition of product requirements. The approach uses natural language processing and formalized design knowledge to extract and provide implicit information from the requirements. This leads to a clear definition of the requirements and KCs and thus creates a founded basis for robustness evaluation at the beginning of the concept design stage. The approach is exemplarily applied to a window lifter.

scholarly journals TOWARDS A VERIFICATION AND VALIDATING TESTING FRAMEWORK TO DEVELOP BESPOKE MEDICAL PRODUCTS IN RESEARCH-FUNDED PROJECTS

2021 ◽  
Vol 1 ◽  
pp. 3199-3208
Author(s):  
Emanuel Balzan ◽  
Pierre Vella ◽  
Philip Farrugia ◽  
Edward Abela ◽  
Glenn Cassar ◽  
...  
Keyword(s):  
Medical Devices ◽  
Early Stage ◽  
Design Stage ◽  
Concept Design ◽  
Proof Of Concept ◽  
Detailed Design ◽  
Testing Framework ◽  
Medical Products ◽  
Manufacturing Technologies ◽  
Validation Testing

AbstractResearch funded projects are often concerned with the development of proof-of-concept products. Consequently, activities related to verification and validation testing (VVT) are often not considered in depth, even though various design iterations are carried out to refine an idea. Furthermore, the introduction of additive manufacturing (AM) has facilitated, in particular, the development of bespoke medical products. End bespoke products, which will be used by relevant stakeholders (e.g. patients and clinicians) are fabricated with the same manufacturing technologies used during prototyping. As a result, the detailed design stage of products fabricated by AM is much shorter. Therefore, to improve the market-readiness of bespoke medical devices, testing must be integrated within the development from an early stage, allowing better planning of resources. To address these issues, in this paper, a comprehensive VVT framework is proposed for research projects, which lack a VVT infrastructure. The framework builds up on previous studies and methods utilised in industry to enable project key experts to capture risks as early as the concept design stage.

Benchmarking of Truss Spar Vortex Induced Motions Derived From CFD With Experiments

2005 ◽  
Author(s):  
John Halkyard ◽  
Senu Sirnivas ◽  
Samuel Holmes ◽  
Yiannis Constantinides ◽  
Owen H. Oakley ◽  
...  
Keyword(s):  
Scale Up ◽  
Vertical Cylinder ◽  
Reynolds Numbers ◽  
Full Scale ◽  
Scale Model ◽  
Current Direction ◽  
Test Results ◽  
Helical Strakes ◽  
Truss Spar ◽  
Scale Data

Floating spar platforms are widely used in the Gulf of Mexico for oil production. The spar is a bluff, vertical cylinder which is subject to Vortex Induced Motions (VIM) when current velocities exceed a few knots. All spars to date have been constructed with helical strakes to mitigate VIM in order to reduce the loads on the risers and moorings. Model tests have indicated that the effectiveness of these strakes is influenced greatly by details of their design, by appurtenances placed on the outside of the hull and by current direction. At this time there is limited full scale data to validate the model test results and little understanding of the mechanisms at work in strake performance. The authors have been investigating the use of CFD as a means for predicting full scale VIM performance and for facilitating the design of spars for reduced VIM. This paper reports on the results of a study to benchmark the CFD results for a truss spar with a set of model experiments carried out in a towing tank. The focus is on the effect of current direction, reduced velocity and strake pitch on the VIM response. The tests were carried out on a 1:40 scale model of an actual truss spar design, and all computations were carried out at model scale. Future study will consider the effect of external appurtenances on the hull and scale-up to full scale Reynolds’ numbers on the results.

A Novel Methodology to Manage Uncertainty for Multidisciplinary Design and Optimization in Conceptual Design

2008 ◽  
Vol 44-46 ◽  
pp. 225-232 ◽  
Author(s):  
Xin Yu Shao ◽  
Xue Zheng Chu ◽  
Liang Gao ◽  
Hao Bo Qiu
Keyword(s):  
Conceptual Design ◽  
Probabilistic Method ◽  
Kriging Model ◽  
Design Stage ◽  
Design And Optimization ◽  
Rough Sets Theory ◽  
Innovative Methodology ◽  
Traditional Approaches ◽  
Sets Theory

Uncertainty in design and simulation affects the quality of product directly during the process of MDO, which should be considered to help designers to make the design decisions, especially at conceptual design stage. In traditional approaches, this uncertainty is ignored in the hope that it is not significant to the decision making. In this investigation, firstly, three main uncertainties in MDO of conceptual design are pointed out and carefully analyzed. Then, an innovative methodology integrating extract knowledge and probabilistic method to manage these uncertainties is presented. Considering practical application and eliminating the uncertainty in configuration, we propose a promising method combining Fuzzy c-means algorithm (FCM) and Rough Sets theory (RST) to deduce the configuration rule. Furthermore, probabilistic kriging model is utilized as an approximation model to reduce global computational expense of complex product. Sensitivity analysis (SA) is used to reduce uncertainty of inputs of simulation, and mean square error (MSE) is employed to assess model error to reduce model uncertainty. Finally, the validity and necessity of this methodology are demonstrated through the conceptual design of bulk carrier.

Conceptual Design of Kenaf Polymer Composites Automotive Spoiler Using TRIZ and Morphology Chart Methods

2015 ◽  
Vol 761 ◽  
pp. 63-67 ◽  
Author(s):  
Muhd Ridzuan Mansor ◽  
S.M. Sapuan ◽  
A. Hambali ◽  
Edi Syam Zainudin ◽  
A.A. Nuraini
Keyword(s):  
Polymer Composites ◽  
Conceptual Design ◽  
New Product Development ◽  
Design Method ◽  
Idea Generation ◽  
Development Stage ◽  
Concept Development ◽  
Design Stage ◽  
Concept Design ◽  
Solution Strategies

Spoilers are part of an automotive exterior bodywork system that acts to create additional down force for higher traction. In this paper, a new conceptual design of automotive spoiler component using kenaf polymer composites was developed using integrated TRIZ and morphology chart design method. The aim is to enable direct application of kenaf polymer composites to the spoiler design to achieve better environmental performance of the component while maintaining the required structural strength for safe and functional operation. The overall process involved two major stages, which are the idea generation and concept development. TRIZ method was applied in the idea generation stage where specific solution strategies for the design were created. In the concept development stage, the specific TRIZ solution strategies obtained were later refined into relevant alternative system elements using Morphology chart method. Finally, a new conceptual design of an automotive spoiler was developed using the combination of the identified system elements. The integrated TRIZ and morphology chart method were found to be new tools that can be used effectively in the concept design stage, especially in cases where direct material substitution is given the main focus for the new product development.

COVIRDS: Shape Modeling in a Virtual Reality Environment

1997 ◽  
Author(s):  
Tushar H. Dani ◽  
Chi-Cheng P. Chu ◽  
Rajit Gadh
Keyword(s):  
Computer Aided Design ◽  
Visual Display ◽  
Design Stage ◽  
Design System ◽  
Concept Design ◽  
Virtual Design ◽  
Cad Systems ◽  
Product Concept ◽  
Shape Models ◽  
Solid Models

Abstract Rapid shape creation and visualization of solid models remains a tedious task despite advances in the field of Computer Aided Design (CAD)/Solid Modeling. CAD systems require a significant level of detail, such as vertices, edges, and faces to be specified by the user, even before the simplest of shapes can be created and viewed. In addition, most CAD systems have an essentially 2D interface for designing artifacts. This makes artifact visualization, for example by interactive rotation, difficult since all manipulations have be achieved by 2D translation of the mouse or by typing in the required angles of rotation. The limited visualization capability and the requirement to create shapes through the specification of low level entities is especially cumbersome in the concept shape design stage. This paper describes the Conceptual Virtual Design System, COVIRDS, a tool for product concept design. COVIRDS provides an intuitive voice and hand input-based interface for modeling of products using a ‘construction’ approach. Product shape models are created by ‘attaching’ simpler parametrically defined ‘Shape Elements’ to other elements to create more complex models. Voice commands are used to instantiate shape elements and change their parameters, for example, the width, length and height of a block element. 3D hand input is used for positioning shape elements during element attachment. The voice and hand input-based interface together with a stereoscopic visual display facilitates rapid creation and visualization of concept shape models.

Installation Engineering Challenges of the World's Heaviest Topside on Steel Substructure

2021 ◽  
Author(s):  
Prasad Kunnathully Prabhakaran ◽  
Cibu Varghese ◽  
Faris Ragheb Kamal
Keyword(s):  
Weight Control ◽  
Oil And Gas ◽  
Load Transfer ◽  
Development Project ◽  
Design Stage ◽  
Gas Treatment ◽  
Field Development ◽  
Gas Processing ◽  
Transfer Method ◽  
Load Transfer Method

Abstract As part of a green field development project for ADNOC offshore, NPCC here in after called as "contractor", successfully completed installation of an oil and gas processing super complex at offshore Abu Dhabi. This super complex consisted of four large interconnected platforms of different functionalities and an accommodation platform. Associated flare structures and interconnecting bridges were also installed as part of this project. Weights of the topsides in this project were varying from 7,000MT to a ∼32,000 MT. All these topsides were installed by float-over method using contractors own cargo /launch barge fleet. Gas treatment platform topside installed as part of the above project is the world's heaviest single-module topside Installed by float-over on a fixed steel jacket. Float-over is the process of installing the topside on a preinstalled jacket by ballasting and/or by other methods of load transfer such as hydraulic jacks. This installation method is widely used for heavy topsides, due to its cost effectiveness and efficiency. By float over installation method, the topside can be installed as a single integrated unit after completion of all hookup and commissioning works onshore. This paper outlines installation engineering challenges during EPC phase for the gas treatment platform topside. Design of this topside went through phenomenal changes in terms of its size and weight during EPC phase and posed several challenges to install this unit as a single module. This paper presents the installation method, and various parameters considered during installation and also includes discussion on selection of float-over barge, importance of weight control & layout design, finalization of topside support height on barge and installation aids. This paper also presents various installation engineering analyses required during design stage. Float-over installation of the gas treatment platform was carried out by the conventional load transfer method (by ballasting) and using normal spread mooring arrangement.

Sign in / Sign up

Export Citation Format

Share Document