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.

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.

Experimental Study and Optimization of a 2.44 Meter Vertical Axis Wind Turbine

2011 ◽  
Author(s):  
Brad Nichols ◽  
Timothy Dimond ◽  
Josh Storer ◽  
Paul Allaire
Keyword(s):  
Wind Tunnel ◽  
Power Output ◽  
Vertical Axis ◽  
Chord Length ◽  
Small Scale ◽  
Physical Parameters ◽  
Wind Tunnel Testing ◽  
Wind Speeds ◽  
The Given ◽  
Tunnel Testing

Vertical axis wind turbines (VAWTs) have long been considered a viable source for alternative energy; however, limited published research has contributed to limited technological advancement in these machines. Slower advancements are due, in part, to their complex aerodynamic models which include wake effects, vortex shedding, and cyclical blade angles of attack and Reynolds numbers. VAWTs are believed to hold several advantages over their more popular and better studied horizontal axis counterparts, including a simpler design and better efficiencies in lower wind speeds. They may have a unique niche in standalone applications at moderate wind speeds such as on an island, a remote military installation, or an inland farm. Currently, no published design standards or criteria exist for optimizing the physical properties of these turbines to maximize power output. A 2.44 m tall VAWT prototype with variable physical parameters was constructed for wind tunnel testing. The purpose of the experiment was to maximize the turbine’s power output by optimizing its physical configuration within the given parameters. These parameters included rotor radius, blade chord length, and pitch offset angle. The prototype was designed as a scaled-down model of a potential future VAWT unit that may be used to sustain a small farm or 2–4 houses. The wind tunnel consisted of a 2.74 m by 1.52 m cross section and could produce maximum wind speeds of 3.56 m/s. The turbine prototype consisted of three sets of interchangeable blades featuring two airfoils of varying chord length. Spokes of varying length allowed for rotor radii of 190.5, 317.5, and 444.5 mm. The pitch offset of the blades was varied from 0°–20° with a focus on the 10°–16° range as preliminary results suggested that this was the optimal range for this turbine. Ramp-up and steady-state rotational speeds were recorded as the blades were interchanged and the turbine radius was varied. A disk brake provided braking torque so that power coefficients could be estimated. This study successfully optimized the turbine’s power output within the given set of test parameters. The importance of finding an appropriate aspect ratio and pitch offset angle are clearly demonstrated in the results. A systematic approach to small scale wind tunnel testing prior to implementation is presented in this paper.

Wind loads on roof-mounted isolated solar panels of tall buildings through wind tunnel testing

Solar Energy ◽  
2022 ◽  
Vol 231 ◽  
pp. 607-622
Author(s):  
S.F. Dai ◽  
H.J. Liu ◽  
J.H. Yang ◽  
H.Y. Peng
Keyword(s):  
Wind Tunnel ◽  
Tall Buildings ◽  
Wind Loads ◽  
Wind Tunnel Testing ◽  
Solar Panels ◽  
Tunnel Testing

Investigation of Aerodynamic Performance of Helical Shape Vertical-Axis Wind Turbine Models With Various Number of Blades Using Wind Tunnel Testing and Computational Fluid Dynamics

2016 ◽  
Author(s):  
Mosfequr Rahman ◽  
Travis Salyers ◽  
Mahbub Ahmed ◽  
Adel ElShahat ◽  
Valentin Soloiu ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Twist Angle ◽  
Average Power ◽  
Vertical Axis ◽  
Aerodynamic Performance ◽  
Power Coefficient ◽  
Wind Tunnel Testing ◽  
Vertical Axis Wind Turbine ◽  
Wind Speeds ◽  
Tunnel Testing

The demand for wind energy as a renewable source is rising substantially. A growing interest exists in utilizing potential energy conversion applications in areas with less powerful and less consistent wind conditions. In these areas, vertical-axis wind turbines (VAWTs) possess several advantages over the conventional horizontal-axis type. Savonius turbines are drag-based rotors which operate due to a pressure difference between the advancing and retreating blades. These turbines are simpler in design, less expensive to install, independent of wind direction, and more efficient at low wind speeds. In the present study, rotors were designed with semi-circle blades consisting of a helical shape with twist angle of 90 degrees. Helical designs spread the torque applied to the rotor over a complete revolution with the purpose of increasing efficiency. Three models were analyzed with different number of blades including 2, 3, and 4 blade models. Models for testing were designed using the CAD software SolidWorks. The blades were then 3D printed with PLA plastic. A consistent swept area was maintained for each model, and only blade number was varied. Subsonic, open-type wind tunnel testing was used for measuring RPM and reactional torque over a range of wind speeds. For the numerical approach, ANSYS Fluent simulations were used for analyzing aerodynamic performance by utilizing moving reference frame and sliding mesh model techniques. Due to the helical twist, the cross-section of the blades varied in the Y-direction. Because of this, a 3-dimensional and transient method was used for accurately solving torque and power coefficients. It has been found that the highest average power coefficient observed in the study is achieved by the Helical2 model (2-bladed helical design VAWT model), both numerically and experimentally.

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