• International Journal of Aerospace System Engineering
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• 제2권1호
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• pp.43-46
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• 2015

Aeroelastic gust response analysis plays an important role in design of aircrafts. For gust response analysis, frequency domain aerodynamics method has been typically used with generalized aerodynamic influence coefficient matrices at various reduced frequencies. However, it cannot be applied to the aeroservoelastic analysis, such as gust alleviation control. Time-domain state space (SS) models must be built. It attacks little attention that gust response analysis relies on continuous gust time-domain input signal in terms of its PSD function. The aim the current study is to provide a reduced-order modeling (ROM) method based on CFD to model gust responses for continuous gust responses for continuou gust inputs in time domain. The paper analyzed the gust response of AGARD445.6 wing subjected to the Dryden gust with ROMs and compared the difference between the rigid structure and elastic one. The results demonstrate that structure elastic effect effect should be considered in the design of aircraft.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1329-1332
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• 2007

In this study, the design method of flexible wing model for gust response measurement wind tunnel test was presented. The design concept proposed herein was validated by modal testing of the flexible wing model manufactured. In addition, aeroservoelastic modeling method for flexible wing model was presented and validated by comparing the gust response analysis results from the method proposed herein with those of commercial software. The gust response characteristics of the flexible wing model was studied by wind tunnel test for measuring the flexible wing gust response due to the induced gust excitation by gust generator. The aeroservoelastic modeling methods proposed and the wind tunnel test results obtained in this study can be applied for wind tunnel testing of the flexible wing for gust response alleviation.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.203-206
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• 2006

In this study, the method of designing the flexible wing model which will be used for wind tunnel testing of gust response alleviation system was presented. The design concept proposed herein was validated by performing the modal testing of the flexible wing model manufactured for demonstration purpose. In addition, the study on the gust response alleviation using flexible wing control surface was performed. For this purpose, optimal control with output feedback was adopted for designing the control surface controller, and the effects of gust response alleviation was validated by performing the numerical simulation for the representative flexible wing model. The methods proposed and validated in this study can be applied for wind tunnel testing of the flexible wing for gust response alleviation.

• International Journal of Aerospace System Engineering
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• 제2권2호
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• pp.44-49
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• 2015

A gust response analyses method based on Reduced Order Models (ROMs) was developed in the paper. Firstly, taken random signal as the input signal and adopt Single Input-Multi-Output (SIMO) training fashion, a ROM based on Auto-Regressive and Moving Average model (ARMA) was established and validated with the comparison of CFD/CSD and experiment. Then, by introducing control surface deflection and control laws, flutter active suppress was studied. Lastly, through filtering and transferring function, the gust temporal signal is obtained based on Dryden gust model, and gust response and suppress were simulated.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계 학술대회논문집(수송기계편)
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• pp.45-48
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• 2005

Tile gust generator was designed for generating the gust field in the wind tunnel test of the scaled flexible wing model for validating gust response alleviation system. The ground operation test was performed for estimating the dynamic performance of tile gust generator before installing it in the wind tunnel for gust field measurement. The ground test results showed that the gust generator has sufficient dynamic capability to simulate the sinusoidal and random motion of the gust generator wing and thus can be used in the wind tunnel test related to gust.

• Wind and Structures
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• 제19권3호
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• pp.339-352
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• 2014

This paper discusses the appropriate duration for basic gust wind speeds in wind loading codes and standards, and in wind engineering generally. Although various proposed definitions are discussed, the 'moving average' gust duration has been widely accepted internationally. The commonly-specified gust duration of 3-seconds, however, is shown to have a significant effect on the high-frequency end of the spectrum of turbulence, and may not be ideally suited for wind engineering purposes. The effective gust durations measured by commonly-used anemometer types are discussed; these are typically considerably shorter than the 'standard' duration of 3 seconds. Using stationary random process theory, the paper gives expected peak factors, $g_u$, as a function of the non-dimensional parameter ($T/{\tau}$), where T is the sample, or reference, time, and ${\tau}$ is the gust duration, and a non-dimensional mean wind speed, $\bar{U}.T/L_u$, where $\bar{U}$ is a mean wind speed, and $L_u$ is the integral length scale of turbulence. The commonly-used Durst relationship, relating gusts of various durations, is shown to correspond to a particular value of turbulence intensity $I_u$, of 16.5%, and is therefore applicable to particular terrain and height situations, and hence should not be applied universally. The effective frontal areas associated with peak gusts of various durations are discussed; this indicates that a gust of 3 seconds has an equivalent frontal area equal to that of a tall building. Finally a generalized gust response factor format, accounting for fluctuating and resonant along-wind loading of structures, applicable to any code is presented.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 추계학술대회 논문집
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• pp.220-225
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• 2013

In this study, active control system using sliding mode control method is presented to achieve the gust response alleviation of a three-dimensional flexible wing model. For this purpose, aeroservoelastic model which is composed of aeroelastic plant, control surface actuator model, and gust model depicting the atmospheric turbulence is formulated in the state space. The aerodynamic force generated by the motion of a trailing edge control surface of a flexible wing is made use of as control means. An active control system combining state feedback sliding mode controller and state estimator based on measured responses such as wing tip acceleration and wing root strain is designed for gust response alleviation of a flexible wing aeroservoelastic model. The performance of the controller designed is demonstrated via numerical simulation for the representative flexible wing model under gust loading conditions.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.452-456
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• 2004

A study on gust loads alleviation using aircraft control surface was performed. Aeroservoelastic model including control surface controller was formulated and validated by comparing the results of continuous turbulence response analysis with those of MSC/NASTRAN. Optimal control with output feedback was adopted for designing the control surface controller, and the effects of gust loads alleviation was validated by performing the numerical simulation for the controller designed.

• Advances in aircraft and spacecraft science
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• 제4권2호
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• pp.125-144
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• 2017

This paper summarises the design of a gust generator and the comparison between high fidelity numerical results and experimental results. The gust generator has been designed for a low subsonic wind tunnel in order to perform gust response experiments on wings and assess load alleviation. Special attention has been given to the different design parameters that influence the shape of the gust velocity profile by means of CFD simulations. Design parameters include frequency of actuation, flow speed, maximum deflection, chord length and gust vane spacing. The numerical results are compared to experimental results obtained using a hot-wire anemometer and flow visualisation by means of a tuft and smoke. The first assessment of the performance of the gust generator showed proper operation of the gust generator across the entire range of interest.

• 한국항공우주학회지
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• 제32권5호
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• pp.30-40
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• 2004

본 연구에서는 비정렬 격자계에서 비행선 돌풍 해석을 위한 해석 프로그램을 개발하였다. 지배방정식으로는 Euler 방정식이 사용되었으며, 비행선의 저마하수 운행 영역에서의 정확하고 효율적인 해석을 위해 저마하수 예조건화 기법을 적용하였다. 돌풍 모형으로는 sharp-edged gust가 사용되었다. 해석 기법의 검증을 위해서는 선형 방정식에 대해서 유도된 해석해와 비교하였으며, 잘 일치하는 것을 알 수 있었다. 실제적인 비행선 형상에 대해서 돌풍의 영향을 받을 때 양력 계수는 매우 큰 변화를 일으키는 반면에 모멘트는 상대적으로 작은 변화를 일으키는 것을 볼 수 있었다. 또한 제어면의 사용으로 인해 더욱 강하게 정적으로 안정하게 되는 것을 알 수 있었다.