• Wind and Structures
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• v.8 no.4
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• pp.269-281
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• 2005

The paper describes the work of the IAWE Working Group WGF - Extreme Wind Prediction and Zoning, one of the international codification working groups set up in 2000. The topics covered are: the international database of extreme winds, quality assurance and data quality, averaging times, return periods, probability distributions and fitting methods, mixed wind climates, directionality effects, the influence of orography, rare events and simulation methods, long-term climate change, and zoning and mapping. Recommendations are given to promote the future alignment of international codes and standards for wind loading.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.1
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• pp.10-20
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• 2017

This study presents the feasibility of CFD(computational fluid dynamic) analysis using the flow angularity wind tunnel test technique. The CFD analyzed data by the flow angularity technique has been constructed as the database to get store trajectories by 6-DOF simulation. The database has been checked out store aerodynamic coefficients by the analyses at each position under wing. After that process, the simulated trajectories by database have been compared with the store trajectories by CTS(Captive Trajectory Simulation) of CFD. The trajectories provided by the database of flow angularity have a good agreement with the store trajectories by CFD.

• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.1
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• pp.45-54
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• 2022

There has been necessity to supplement the fin database to improve the accuracy of low-fidelity aerodynamic solver for missile configuration. In this study, fin database is expanded by in-house solver, utilized in the triservice data the previously established into regions beyond means of CFD. Fin alone data of CFD analysis results in the original region is matched well with triservice data originated from the wind tunnel tests. Extensive fin aerodynamic data from CFD analysis is added to the existing database of the low-fidelity solver. For confirmation, aerodynamic characteristics of body-tail and body-canard-tail missile configurations is computed using upgraded low-fidelity solver at transonic region. The result using improved solver shows good agreements with wind tunnel test and CFD analysis results, which implies that it becomes more accurate.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.5
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• pp.422-431
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• 2015

Wind tunnel testing to construct static aerodynamic database of KF-16 was conducted for preceding research of design of experiments in wind tunnel testing. The test model is KF-16 scaled 1/33 and it has horizontal tail, flaperon, and rudder. The experiments consist of one experiment for analyzing aerodynamic coefficients under whether or not horizontal tail is present and four experiments for analyzing aerodynamic coefficients of changes of deflection angle in control surface which are flap, flaperon, rudder, and horizontal tail. After conducting wind tunnel testing, the experimental results show that the control surface changes have a great effect on Aerodynamic characteristics.

• Journal of Power System Engineering
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• v.19 no.2
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• pp.5-14
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• 2015

This investigation presents reviews of many research results on lightning damage to wind turbines and lightning protection strategies from IEC Standard, Europe, USA, Japan and Korea. There have been few studies on lightning protection of wind turbines in Korea, while various investigations have been performed in the other countries. It is necessary to apply some good lightning protection strategies of IEC Standard and the other countries to Korea. Those are as follows: The guideline for lightning protection of wind turbines should be established based on IEC Standards. It needs to be carried out both development of software and experimental studies for understanding the types of lightning damage to wind turbines and compiling the database. In order to minimize the lightning damage to wind turbines, it is a key factor for wind farm owners and researchers to provide the information about the damage cases and wind farm operation technique.

• International Journal of High-Rise Buildings
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• v.2 no.3
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• pp.257-269
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• 2013

This study presents the development of an advanced multiple database-enabled design module for high-rise buildings (DEDM-HR), which seamlessly pools databases of multiple high frequency base balance measurements from geographically dispersed locations and merges them together to expand the number of available building configurations for the preliminary design. This feature offers a new direction for the research and professional communities that can be utilized to efficiently pool multiple databases therefore expanding the capability of an individual database and improving the reliability of design estimates. This is demonstrated, in this study, by the unprecedented fusion of two major established databases, which facilitates interoperability. The DEDM-HR employs a cyberbased on-line framework designed with user-friendly/intuitive web interfaces for the convenient estimation of wind-induced responses in the alongwind, acrosswind and torsional directions with minimal user input. In addition, the DEDM-HR embeds a novel feature that allows the use of wind characteristics defined in a code/standard to be used in conjunction with the database. This supplements the provisions of a specific code/standard as in many cases guidance on the acrosswind and torsional response estimates is lacking. Through an example, results from several international codes and standards and the DEDM-HR with the embedded features are compared. This provision enhances the scope of the DEDM-HR in providing an alternative design tool with nested general provisions of various international codes and standards.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.762-767
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• 2008

Estimated values for maximum lift coefficients of a light airplane, ChanGong-91, derived from an analytical method using a test database, a computational fluid dynamic method, a wind tunnel test, and a flight test are compared. The DATCOM method and VSAERO code are applied as the analytical method and the computational fluid dynamic method, respectively, in order to estimate the maximum lift coefficients of a light airplane. The wind tunnel test is conducted using a 1/14.5 scaled model installed in a closed circuit type wind tunnel. For the flight test approach, the wings-level power-off stall tests are performed to obtain the maximum lift coefficients. As a point of reference for the flight test results of the maximum lift coefficients, the differences of both estimates derived from the DATCOM method and the wind tunnel test data are smaller than those derived from VSAERO.

• Journal of computational fluids engineering
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• v.19 no.2
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• pp.86-92
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• 2014

In this paper, prediction of separation trajectory for Two-stage-To-Orbit space launch vehicle has been numerically simulated by using an aerodynamic database based on steady state analysis. Aerodynamic database were obtained for matrix of longitudinal and vertical positions. The steady flow simulations around the launch vehicle have been made by using a 3-D RANS flow solver based on unstructured meshes. For this purpose, a vertex-centered finite-volume method was adopted to discretize inviscid and viscous fluxes. Roe's finite difference splitting was utilized to discretize the inviscid fluxes, and the viscous fluxes were computed based on central differencing. To validate this flow solver, calculations were made for the wind-tunnel experiment model of the LGBB TSTO vehicle configuration on steady state conditions. Aerodynamic database was constructed by using flow simulations based on test matrix from the wind-tunnel experiment. ANN(Artificial Neural Network) was applied to construct interpolation function among aerodynamic variables. Separation trajectory for TSTO launch vehicle was predicted from 6-DOF equation of motion based on the interpolated function. The result of present separation trajectory calculation was compared with the trajectory using experimental database. The predicted results for the separation trajectory shows fair agreement with reference[4] solution.

• Wind and Structures
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• v.36 no.6
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• pp.405-421
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• 2023

Strong wind is the main factors of wind-damage of high-rise buildings, which often creates largely economical losses and casualties. Wind pressure plays a critical role in wind effects on buildings. To obtain the high-resolution wind pressure field, it often requires massive pressure taps. In this study, two traditional methods, including bilinear and bicubic interpolation, and two deep learning techniques including Residual Networks (ResNet) and Generative Adversarial Networks (GANs), are employed to reconstruct wind pressure filed from limited pressure taps on the surface of an ideal building from TPU database. It was found that the GANs model exhibits the best performance in reconstructing the wind pressure field. Meanwhile, it was confirmed that k-means clustering based retained pressure taps as model input can significantly improve the reconstruction ability of GANs model. Finally, the generalization ability of k-means clustering based GANs model in reconstructing wind pressure field is verified by an actual engineering structure. Importantly, the k-means clustering based GANs model can achieve satisfactory reconstruction in wind pressure field under the inputs processing by k-means clustering, even the 20% of pressure taps. Therefore, it is expected to save a huge number of pressure taps under the field reconstruction and achieve timely and accurately reconstruction of wind pressure field under k-means clustering based GANs model.

• Atmosphere
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• v.15 no.4
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• pp.191-202
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• 2005

This study was conducted to estimate how vertically high and horizontally long a sea breeze occurred around Gangneung of the Korean peninsula would be reached to an inland. Geographically, gangneung is located on the center of the east coast shaping an arc, and a coastal line around gangneung has a form extending northwestward and southeastward, respectively. Therefore, an inflow of the northerly has similar effects of the sea breeze since a deep valley of Daegwallyeong, which is one of main ridges of the Taebaek mountains, not only reaches northeastward up to this region but also plays the part of the steering gear changing a wind direction from northerly to easterly, this is, the wind from sea. First of all, the study had defined the sea breeze as a wind blown from NNE to ESE, clockwise. And then, we analyzed characteristics of the sea breeze occurred around gangneung in view of the maximum wind speed and the wind direction for October 1st, 2003 through September 30th, 2004, the upper air database for May through June of 2004, and the wind vector database of AWS (Automatic Weather System). All meteorological information is collected at the weather station of gangneung and by the AWS which is being scattered around this region. Finally, the study figures out that how horizontally long a sea breeze would be reached depends on a level of the easterly inflow. At the first step of the inflow of the sea breeze, the wind from NNW blows into this region by keeping up the speed $3m{\cdot}s^{-1}$, and effects of the northerly are dominated with time and the wind at the inland blows out southwestward cause of the surface friction at the next step. On the other hand, there is no change of wind direction in the inflow at Daegwallyeong because a surface friction of there is smaller than around gangneung, relatively. In other word, the easterly blows toward Daegwallyeong. However, the wind speed is not higher than that of the coast around gangneung.