• Title, Summary, Keyword: gust response

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Identification of Aerodynamic Model CFD-Based for Gust Response Analysis

  • Nie, Xueyuan;Yang, Guowei
    • International Journal of Aerospace System Engineering
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    • v.2 no.1
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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.

Study of Gust Response Characteristics for Flexible Wing by Wind Tunnel Test (풍동시험을 통한 유연날개 돌풍응답 특성 분석)

  • Lee, Sang-Wook;Kim, Tae-Uk;Hwang, In-Hee;Im, Jae-Hyung;Ha, Chul-Keun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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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.

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Gust Response and Active Suppress based on Reduced Order Models

  • Yang, Guowei;Nie, Xueyuan;Zheng, Guannan
    • International Journal of Aerospace System Engineering
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    • v.2 no.2
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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.

Design and Ground Test of Gust Generator for GLA Wind Tunnel Test (돌풍하중완화 풍동시험을 위한 돌풍발생장치 설계 및 지상시험)

  • Lee, Sang-Wook;Kim, Tae-Uk;Kim, Sung-Chan;Hwang, In-Hee;Ha, Chul-Keun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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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.

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Gust Response Alleviation of a Three-dimensional Flexible Wing using Sliding Mode Control (슬라이딩 모드 제어기법을 이용한 3차원 유연날개 돌풍응답 제어)

  • Lee, Sang-Wook;Suk, Jinyoung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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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.

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Design and Numerical Analysis of Flexible Wing for Gust Response Alleviation (유연 날개 설계 및 돌풍응답완화 수치해석)

  • Lee, Sang-Wook;Kim, Tae-Uk;Kim, Sung-Chan;Hwang, In-Hee;Ha, Chul-Keun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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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.

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Gust durations, gust factors and gust response factors in wind codes and standards

  • Holmes, John D.;Allsop, Andrew C.;Ginger, John D.
    • Wind and Structures
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    • v.19 no.3
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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.

Design and testing of a low subsonic wind tunnel gust generator

  • Lancelot, Paul M.G.J.;Sodja, Jurij;Werter, Noud P.M.;Breuker, Roeland De
    • Advances in aircraft and spacecraft science
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    • v.4 no.2
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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.

Analysis of Airship Gust Response Using Low Mach Number Preconditioning (저마하수 예조건화 기법을 이용한 비행선의 돌풍 응답 해석)

  • Kim, Joo-Sung;Nam, Hwa-Jin;Kwon, Oh-Joon;Yeom, Chan-Hong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.32 no.5
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    • pp.30-40
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    • 2004
  • In the present study, a numerical method has been developed for the calculation of the gust response of an airship using unstructured meshes. A preconditioning method is incorporated for accurate and efficient computations of the Euler equations at the low Mach number range. A simple sharp-edged gust is used as a gust model. The accuracy of the present method is demonstrated through comparisons with an exact line theory. The numerical results show that the variation of lift is relatively larger than that of moment. It is also shown that the static stability of the airship is enhanced with the use of control fins.

Dynamic Response Control of a Flexible Wing using Sliding Mode Control (슬라이딩 모드 제어기법을 이용한 유연날개 동적 응답 제어)

  • Lee, Sang-Wook;Suk, Jinyoung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.522-527
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    • 2013
  • In this study, dynamic response control of a flexible wing such as gust loads alleviation using sliding mode control method is presented. To achieve this purpose, trailing edge control surface of a flexible wing is used as control means generating the aerodynamic control force. Aeroservoelastic CASE) model consisting of aeroelastic plant, control surface actuator model, and gust model depicting the atmospheric turbulence is formulated in the state space. A sliding mode controller based on the estimated state vector is designed for active dynamic response control of flexible wing aeroservoelastic model. The performance of the controller designed is demonstrated via numerical simulation for the representative flexible wing model under atmospheric turbulence loading.

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