• International Journal of Aeronautical and Space Sciences
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• v.2 no.1
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• pp.103-109
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• 2001

Productivity enhancement program of wind tunnel testing has begun at Korea Aerospace Research Institute Low Speed Wind Tunnel (KARI LSWT). A previous test record of a canard airplane model was adopted to examine the current status of wind tunnel testing efficiency. The time consumed to perform testing activities from the model preparation to data collection was broken down and the results were compared with those of the recent Boeing low speed test result. The efforts to improve the wind tunnel productivity consisted of the installation of mini crane underneath of test section, fabricating lift device for image fairings, model configuration changing rigs and the modifications of external balance system. Time reductions for changing strut interface platform and installation of image fairings. These effects showed more than 70% improvement over the previous test time. Integration of the new and modified systems will improve productivity of wind tunnel testing in KARI LSWT.

• Wind and Structures
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• v.35 no.2
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• pp.83-92
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• 2022

When the rolling stocks run on the curve, the external rail has to be lifted to a certain level to balance the centrifugal force acting on the train body. Under such a situation, passengers may feel uncomfortable, and the slanted vehicle has the potential overturning risks at high speed. This paper conducted a wind tunnel test in an annular wind tunnel with φ=3.2 m based on a 1/20^th scaled high-speed train (HST) model. The sensitivity of Reynolds effects ranging from Re = 0.37×10⁶ to Re = 1.45×106 was tested based on the incoming wind from U=30 m/s to U=113 m/s. The wind speed covers the range from incompressible to compressible. The impact of roll angle ranging from γ=0° to γ=4° on train aerodynamics was tested. In addition, the boundary layer development was also analyzed under different wind speeds. The results indicate that drag and lift aerodynamic coefficients gradually stabilized and converged over U=70 m/s, which could be regeared as the self-similarity region. Similarly, the thickness of the boundary layer on the floor gradually decreased with the wind speed increase, and little changed over U=80 m/s. The rolling moment of the head and tail cars increased with the roll angle from γ=0° to γ=4°. However, the potential overturning risks of the head car are higher than the tail car with the increase of the roll angle. This study is significant in providing a reference for the overturning assessment of HST.

• International Journal of Aeronautical and Space Sciences
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• v.1 no.2
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• pp.68-74
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• 2000

A comparative wind tunnel testing of an airplane model was performed at the Korea Aerospace Research Institute Low Speed Wind tunnel(KARI LSWT). The model used for the comparative test was a seaplane model from the Glenn L. Martin Wind(GLM) Tunnel of University of Maryland, U.S.A. The 6-component external balance used in force and moment measurement is pyramidal type, which is a precision device that has strain gauge-type load cell inside of balance and the virtual center of the balance coincides with the tunnel centerline. Image method is adopted to eliminate the tare and interference of the model support, and to correct the flow angularity to the model also. Test results from KARI LSWT were compared with the results from GLM tunnel.

• Wind and Structures
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• v.31 no.4
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• pp.335-350
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• 2020

In coastal residential communities, especially along the coastline, flooding is a frequent natural hazard that impacts the area. To reduce the adverse effects of flooding, it is recommended to elevate coastal buildings to a certain safe level. However, post storm damage assessment has revealed severe damages sustained by elevated buildings' components such as roofs, walls, and floors. By elevating a structure and creating air gap underneath the floor, the wind velocity increases and the aerodynamics change. This results in varying wind loading and pressure distribution that are different from their slab on grade counterparts. To fill the current knowledge gap, a large-scale aerodynamic wind testing was conducted at the Wall of Wind experimental facility to evaluate the wind pressure distribution over the surfaces of a low-rise gable roof single-story elevated house. The study considered three different stilt heights. This paper presents the observed changes in local and area averaged peak pressure coefficients for the building surfaces of the studied cases. The aerodynamics of the elevated structures are explained. Comparisons are done with ASCE 7-16 and AS/NZS 1170.2 wind loading standards. For the floor surface, the study suggests a wind pressure zoning and pressure coefficients for each stilt height.

• Wind and Structures
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• v.9 no.5
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• pp.369-386
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• 2006

A combination Aerodynamic/Atmospheric Boundary Layer (AABL) Wind and Gust Tunnel with a unique active gust generation capability has been developed for wind engineering and industrial aerodynamics applications. This facility is a cornerstone component of the Wind Simulation and Testing (WiST) Laboratory of the Department of Aerospace Engineering at Iowa State University (ISU). The AABL Wind and Gust tunnel is primarily a closed-circuit tunnel that can be also operated in open-return mode. It is designed to accommodate two test sections ($2.44m{\times}1.83m$ and $2.44m{\times}2.21m$) with a maximum wind speed capability of 53 m/s. The gust generator is capable of producing non-stationary gust magnitudes around 27% of the mean flow speed. This paper describes the motivation for developing this gust generator and the work related to its design and testing.

• Bulletin of the Korean Space Science Society
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• 2004.10b
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• pp.258-261
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• 2004

Numerical simulations are made to predict the axial force coefficients of a two-stage launch vehicle, and the results are compared with those by wind tunnel tests. It is found that the forebody axial force is not affected by whether the base of the body is modeled or not. Modeling the sting support used in wind tunnel tests reduced the base axial force compared to the results without it. The present calculation shows that the forebody axial forces are underestimated while the base axial forces are overestimated. The total axial force, therefore, compares with the experimental data with better accuracy by cancelling out the errors of opposite signs. Modeling of the sting support in numerical simulations is found to be necessary to get a better agreement with the experiments for both base and overall axial force coefficients.

• International Journal of Aeronautical and Space Sciences
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• v.4 no.1
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• pp.19-25
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• 2003

A low speed wind tunnel test for the canard airplane model was conducted in KARI LSWT. To measure the required level of accuracy, the image system was applied for all elevator deflection and different canard incidence conditions. By doing so, the difference in aerodynamic characteristics between the forward swept and straight canards can be precisely evaluated, and the pros and cons of both canards arrangements can be discussed. Compared with both canard configurations at the same incidence angle setting, the straight canard has benefits in lift and drag, and the slope of pitching moment increases more moderately than the forward swept canard. The listed data and discussion would be useful to whom wants to design a canard airplane.

• Wind and Structures
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• v.5 no.2_3_4
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• pp.193-208
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• 2002

Previous studies have shown that Computational Wind Engineering (CWE) is still in its infancy and has a long way to go to become truly useful to the design practitioner. The present work focuses on more recent studies to identify progress on outstanding issues and improvements in the numerical simulation of wind effects on buildings. The paper reviews wind loading and environmental effects; it finds that, in spite of some interesting and visually impressive results produced with CWE, the numerical wind tunnel is still virtual rather than real and many more parallel studies - numerical and experimental - will be required to increase the level of confidence in the computational results.

• Wind and Structures
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• v.5 no.2_3_4
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• pp.257-266
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• 2002

In the recent years flow around bridges are investigated using computer modeling. Selvam (1998), Selvam and Bosch (1999), Frandsen and McRobie (1999) used finite element procedures. Larsen and Walther (1997) used discrete vorticity procedure. The aeroelastic instability is a major criterion to be checked for long span bridges. If the wind speed experienced by a bridge is greater than the critical wind speed for flutter, then the bridge fails due to aeroelastic instability. Larsen and Walther (1997) computed the critical velocity for flutter using discrete vortex method similar to wind tunnel procedures. In this work, the critical velocity for flutter will be calculated directly (free oscillation procedure) similar to the approaches reported by Selvam et al. (1998). It is expected that the computational time required to compute the critical velocity using this approach may be much shorter than the traditional approach. The computed critical flutter velocity of 69 m/s is in reasonable comparison with wind tunnel measurement. The no flutter and flutter conditions are illustrated using the bridge response in time.

• Wind and Structures
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• v.20 no.2
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• pp.117-142
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• 2015

The performance of bridges under strong wind and traffic is of great importance to set the traveling speed limit or to make operational decisions for severe weather, such as controlling traffic or even closing the bridge. Meanwhile, the vehicle's safety is highly concerned when it is running on bridges or highways under strong wind. During the past two decades, researchers have made significant contributions to the simulation of the wind-vehicle-bridge system and their interactive effects. This paper aims to provide a comprehensive review of the overall performance of the bridge and traffic system under strong wind, including bridge structures and vehicles, and the associated mitigation efforts.