Wind tunnel testing and computational fluid dynamics in FLNG and floating production system design

2016 ◽  
Vol 56 (2) ◽  
pp. 613
Author(s):  
Johnathan Green ◽  
Subajan Sivandran
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Numerical Modelling ◽  
Full Range ◽  
Wind Tunnel Testing ◽  
Advantages And Disadvantages ◽  
Time Histories ◽  
The Impact ◽  
Tunnel Testing

Demonstrating how numerical modelling, such as computational fluid dynamics (CFD), can be used to validate results from detailed physical wind tunnel models of FLNG vessels and floating systems is the objective of this extended abstract. 3D rapid prototyping is used to build detailed physical wind tunnel models. This physical model (normally of an approximate scale of 1:200) is then placed in a wind tunnel facility to measure the time histories of the wind loads for a full range of wind directions and a range of drafts. CFD is then used to validate the wind tunnel modelling results. Numerical modelling can also be used to analyse a number of different issues such as the impact of turbine exhaust dispersion, and turbulence on helicopter operations and resulting helideck availability. This extended abstract discusses the importance of wind tunnel testing and numerical modelling during the design phase. The idea that numerical modelling does not replace pure theoretical or experimental results, but acts to complement them with gaining a greater overall picture, will be highlighted. Findings will be presented to discuss the advantages and disadvantages of both approaches, and highlight results such as wind shear and turbulence impacts being best calculated through wind tunnel testing. The extended abstract demonstrates that, ideally during the design process, wind tunnel testing should be followed by numerical modelling to interpolate results.

Wind Tunnel Testing and Computational Fluid Dynamics Analysis of a Wing-in-Ground Effect Vehicle

2007 ◽  
Author(s):  
Boonseng Soh ◽  
Andrew Low ◽  
Cees Bil ◽  
Brendon Bobbermien
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Ground Effect ◽  
Wind Tunnel Testing ◽  
Cfd Modelling ◽  
Aerodynamic Analysis ◽  
Computational Fluid Dynamics Analysis ◽  
Wing In Ground Effect ◽  
Tunnel Testing

The Wing-in-Ground Effect Concept Technology Demonstrator (WIGE CTD) project is a joint venture between Advanced Aerosystem Technologies Pty Ltd and RMIT University, aiming to design, validate and build a prototype recreational vehicle to fly two passengers over a distance of 500km at approximately 120km/h. The WIGE vehicle will fly very close to the surface, usually water, taking advantage of ground effect to transport passengers with a greater lift/drag ratio, and thus greater fuel-efficiency than conventional aircraft. Following preliminary design, an aerodynamic analysis of the vehicle was performed using wind tunnel testing and Computational Fluid Dynamics (CFD). This paper describes the methods used for wind tunnel testing and CFD modelling of the WIGE CTD design. Results obtained using the two approaches are compared with the aim of validating the CFD model and the techniques used in both wind tunnel and CFD modelling for use in future analyses. In addition to the aerodynamic analysis, a basic CFD prediction of the maximum hydrodynamic drag experienced during take off was attempted using a simple model of the WIGE vehicle hull. This result is required in order to ensure that the aquatic take off required by WIGE vehicles was possible for the design. Concurrently, the feasibility of using a general-purpose CFD solver like Fluent to analyse hull performance was also evaluated through this aspect of the investigation.

Numerical and Experimental Study of Turbulent Flows Around Clark Y-14 Aerofoil

2015 ◽  
Author(s):  
Kshitij Vadake ◽  
Jie Cui
Keyword(s):  
Fluid Dynamics ◽  
Wind Tunnel ◽  
Real World ◽  
Force Measurement ◽  
Test Model ◽  
Wind Tunnel Testing ◽  
Cfd Simulations ◽  
Measurement Device ◽  
Tunnel Testing

Experimental Fluid Dynamics (EFD) and Computational Fluid Dynamics (CFD) have been instrumental in Fluid Mechanics to help solve scientific and engineering problems. This research attempts to use both techniques to perform a parametric study of turbulence flow around airfoil ClarkY-14 at various velocity and angle of attack (AoA). Clark Y-14 airfoil was designed in the 1920’s. It demonstrated good overall performance at low and moderate Reynolds numbers. With the progress in the aviation field, its performance was sub-optimal for newer aircraft designs. However, with the advent of RC airplanes and model aircrafts, there is a renewed interest in this airfoil. Various research projects have been conducted using this airfoil, but there hasn’t been a combined EFD and CFD study of the performance characteristics of the airfoil itself, which still finds real world applications today. One important aspect of this research included the investigation of the effects of a Force Measurement Device/Sensor, which is typically used in scaled/full-size wind tunnels to mount the test model as well as measure the forces/moments acting on it during the testing. The presence of such a device could affect the quality of the data obtained from the wind tunnel testing when compared to a real world application scenario where the aforementioned device may not be present. To the best of the author’s knowledge, no detailed study has been published on the effects of such devices. In this study, the results with and without the measuring device were generated by using CFD simulations. The results were then compared to see to what extent the inclusion of these devices will affect the results. The methodology used for this research was experimental as well as computational. In the present research, a commercially available CFD software STAR-CCM+ was employed to simulate the flows around airfoil Clark Y-14. The experimental data was obtained from wind tunnel tests using AEROLAB Educational Wind Tunnel (EWT) and compared with the simulation data from the CFD. The two data sets were in good agreement. Both experimental and simulation results were used to understand the effects of the measurement device/sensor used in the scaled wind tunnel on the lift and drag coefficients of the airfoil. Two separate CFD simulation setups were designed to model the presence and absence of the measurement device/sensor. These setups replicated the wind tunnel setup. The airfoil was tested and simulated at different speeds as well as different AoA. The comparative study gave a useful insight on the accuracy of the CFD simulations in relation to the actual testing. The analysis of results concluded that the force measurement device/sensor had insignificant effects on the accuracy and quality of data collected through wind tunnel testing.

Functional Prototyping and Tooling of FDM Additive Manufactured Parts

2014 ◽  
Author(s):  
Farzad Rayegani ◽  
Godfrey C. Onwubolu ◽  
Attila Nagy ◽  
Hargurdeep Singh
Keyword(s):  
Fluid Dynamics ◽  
Additive Manufacturing ◽  
Wind Tunnel ◽  
Wind Tunnel Testing ◽  
Tool Paths ◽  
Aerodynamic Properties ◽  
Vacuum Forming ◽  
Computational Fluid Dynamics Cfd ◽  
Functional Prototype ◽  
Tunnel Testing

In this paper, we present two additive manufacturing applications: (1) vacuum forming tooling using AM; (2) rocket functional prototype using AM for computational fluid dynamics (CFD) and wind-tunnel testing. The first application shows how additive manufacturing (AM) facilitates the manufacture of vacuum formed parts, which allows such parts to be easily produced especially in the manufacturing sector. We show how combining the advantages of the CAD and FDM technology, vacuum forming can be completed quickly, efficiently and cost effectively. The paper shows that using modified build parameters, the tools FDM creates can be inherently porous, which eliminates the time needed for drilling vent holes that are necessary for other vacuum forming tools, while improving part quality with an evenly distributed vacuum draw. Using SolidWorks CAD software, the model of the tool is created. The STL file is exported to the Insight software, and we present how the Tool Paths Custom Group feature is applied to optimize the tool-paths file and then sent to the FDM system that prints the tooling from ABS engineering thermoplastic. The tooling is then used in the Formech 686 manual vacuum forming machine to produce the vacuum formed part. The second application shows how additive manufacturing (AM) has been applied to producing functional model for wind–tunnel testing, as well as providing computational fluid dynamics (CFD) tool for comparing results obtained from the wind-tunnel testing. The present work is focused on applications of FDM technology for manufacturing wind tunnel test models. The CAD model of a rocket was analyzed for its aerodynamic properties and its functional prototype produced using AM for use in wind–tunnel testing so as to verify and tune the aerodynamic properties. Initial wall conditions were defined for the rocket in terms of the air velocity. The flow simulation was carried out and the goals examined are the velocity and pressure fields around the rocket model. The paper examines some practical issues that arise between how the model geometry for CDF process differs from that that of the FDM process. Consequently, we show that AM-based fused deposition modeling (FDM) technology is faster, less expensive and more efficient than traditional manufacturing processes for vacuum forming and for rapid prototyping of function models for wind-tunnel applications.

scholarly journals Effects of Topside Structures and Wind Profile on Wind Tunnel Testing of FPSO Vessel Models

2020 ◽  
Vol 8 (6) ◽  
pp. 422
Author(s):  
Seungho Lee ◽  
Sanghun Lee ◽  
Soon-Duck Kwon
Keyword(s):  
Wind Tunnel ◽  
Operating Mode ◽  
Wind Loads ◽  
Wind Tunnel Testing ◽  
Wind Speeds ◽  
Medium Level ◽  
Wind Profiles ◽  
The Impact ◽  
Gantry Cranes ◽  
Tunnel Testing

This study examined the effects of wind loads on a floating production storage and offloading (FPSO) vessel, focusing in particular on the impact of the turbulent wind profiles, the level of details of the topside structures, and the operation modes of the gantry cranes. A series of wind tunnel tests were performed on the FPSO vessel model, developed with a scale of 1:200. It was observed that the wind loads measured using a low-detail model were often greater than those measured using a high-detail model. The measured wind loads corresponding to the Norwegian Maritime Directorate (NMD) profile with an exponent of 0.14, were approximately 19% greater than those corresponding to the Frøya profile in the entire range of wind directions, because of the slightly higher mean wind speeds of the NMD profile. The wind forces increased by up to 8.6% when the cranes were at operating mode compared to when they were at parking mode. In view of the observations made regarding the detail level of the tested models, a medium-level detail FPSO model can be considered adequate for the wind tunnel testing if a high-detail model is not available.

Effective Wind Tunnel Testing of Yacht Sails Using a Real-Time Velocity Prediction Program

2011 ◽  
Author(s):  
David Le Pelley ◽  
Peter Richards
Keyword(s):  
Wind Tunnel ◽  
Real Time ◽  
Full Range ◽  
Cost Effective ◽  
Recognition System ◽  
Wind Tunnel Testing ◽  
Prediction Program ◽  
Effective Manner ◽  
Accuracy And Repeatability ◽  
Tunnel Testing

Wind tunnel testing to determine yacht performance has been carried out for at least the last 50 years. A common perception is that experimental methods do not improve significantly over time. This paper shows how modern wind tunnel testing is still the only realistic way of providing a complete picture of aerodynamic performance over a full range of conditions in a rapid and cost-effective manner. The use of a Real-Time VPP and a sail shape recognition system combine to enhance the accuracy and repeatability of testing. The influence of examining boat speed instead of driving force is investigated.

Effect of the inter-car gap length on the aerodynamic characteristics of a high-speed train

2018 ◽  
Vol 233 (4) ◽  
pp. 448-465 ◽  
Author(s):  
Tian Li ◽  
Ming Li ◽  
Zheng Wang ◽  
Jiye Zhang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Drag Force ◽  
High Speed ◽  
Aerodynamic Drag ◽  
Aerodynamic Characteristics ◽  
High Speed Train ◽  
Wind Tunnel Experiments ◽  
The Impact

In wind tunnel experiments, the inter-car gaps are designed in such a way as to separate the force measurements for each car and prevent the interference between cars during tests. Moreover, the inter-car gap has a significant effect on the aerodynamic drag of a train. In order to guide the design of the inter-car gaps between cars in wind tunnel experiments, the impact of the inter-car gap length on the aerodynamic characteristics of a 1/8th scale high-speed train is investigated using computational fluid dynamics. The shear stress transport k-ω model is used to simulate the flow around a high-speed train. The aerodynamic characteristics of the train with 10 different inter-car gap lengths are numerically simulated and compared. The 10 different inter-car gap lengths are 5, 8, 10, 15, 20, 30, 40, 50, 60, and 80 mm. Results indicate that the aerodynamic drag coefficients obtained using computational fluid dynamics fit the experimental data well. Rapid pressure variations appear in the upper and lower parts of the inter-car gaps. With the increase of the inter-car gap length, the drag force coefficient of the head car gradually increases. The total drag force coefficients of the trains with the inter-car gap length less than 10 mm are practically equal to those of the trains without inter-car gaps. Therefore, it can be concluded from the present study that 10 mm is recommended as the inter-car gap length for the 1/8th scale high-speed train models in wind tunnel experiments.

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