Flow and Aeroelastic Control

A special issue of Fluids (ISSN 2311-5521).

Deadline for manuscript submissions: closed (20 March 2021) | Viewed by 19187

Special Issue Editors


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Guest Editor
Aerospace Engineering and Aviation, School of Engineering, RMIT University, Melbourne, VIC 3001, Australia
Interests: aeroelasticity; flow-structure-interaction; active/passive Control; structural dynamics; aerodynamics; solid/fluid mechanics; UAV; composite structures; advanced materials and smart structures; modelling and simulation; ROMs

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Guest Editor
Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629HS Delft, The Netherlands
Interests: aeroelasticity; composite structure tailoring; adaptive materials

Special Issue Information

Dear Colleagues,

A CO2 neutral growth for the aviation industry can be achieved in two ways. Either radically changing propulsion and aircraft configurations or making current configurations more weight and aerodynamically efficient. The most likely way of making the latter happen is to control the flow and the aeroelastic static and dynamic loads.

This issue is dedicated to the newest advances in the areas of active and passive aeroelastic control of static and dynamic loads, as well as active flutter suppression. Furthermore, also aerodynamic control methods are welcomed in this Special Issue.

The topics of interest include, but are not limited to, (nonlinear) control law design for loads and flutter, control system architecture optimisation, high fidelity loads prediction and control, passive loads control through structural tailoring, smart structures concepts for loads control, plasma and synthetic jet actuator for flow control, high fidelity aerodynamics transition modelling including control and reduced-order modelling of flow control.

We would gladly accept your contribution by early 2020. You are welcome to propose other topics within the area of aeroelastic and flow control.

Prof. Pier Marzocca
Prof. Roeland De Breuker
Guest Editors

Manuscript Submission Information

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Keywords

  • static and dynamic load prediction and control
  • active flutter control
  • hybrid and natural laminar flow control
  • flow control modelling and simulation

Published Papers (6 papers)

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Research

32 pages, 20788 KiB  
Article
Controlling the Chaotic Motions of an Airfoil with a Nonlinear Stiffness Using Closed-Loop Harmonic Parametric Excitation
by Robert Bruce Alstrom
Fluids 2020, 5(4), 165; https://doi.org/10.3390/fluids5040165 - 28 Sep 2020
Cited by 1 | Viewed by 2369
Abstract
The purpose of this research is to conduct a preliminary investigation into the possibility of suppressing the flutter and post-flutter (chaotic) responses of a two-dimensional self-excited airfoil with a cubic nonlinear stiffness (in torsion) and linear viscous damping via closed-loop harmonic parametric excitation. [...] Read more.
The purpose of this research is to conduct a preliminary investigation into the possibility of suppressing the flutter and post-flutter (chaotic) responses of a two-dimensional self-excited airfoil with a cubic nonlinear stiffness (in torsion) and linear viscous damping via closed-loop harmonic parametric excitation. It was found that the initial configuration of the proposed control scheme caused the torsional/pitch dynamics to act as a nonlinear energy sink; as a result, it was identified that the mechanisms of vibration suppression are the resonance capture cascade and the short duration or isolated resonance capture. It is the isolated resonance capture that is responsible for the second-order-like damping and full vibration suppression of the aeroelastic system. The unforced and closed-loop system was subjected to random excitation to simulate aerodynamic turbulence. It was found that the random excitation suppresses the phase-coherent chaotic response, and the closed-loop system is susceptible to random excitation. Full article
(This article belongs to the Special Issue Flow and Aeroelastic Control)
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27 pages, 4144 KiB  
Article
Active Flow Control on a Square-Back Road Vehicle
by Juan José Cerutti, Costantino Sardu, Gioacchino Cafiero and Gaetano Iuso
Fluids 2020, 5(2), 55; https://doi.org/10.3390/fluids5020055 - 21 Apr 2020
Cited by 13 | Viewed by 3468
Abstract
An experimental investigation focused on the manipulation of the wake generated by a square back car model is presented. Four continuously-blowing rectangular slot jets were mounted on the rear face of a 1:10 commercial van model. Load cell measurements evidence drag reduction for [...] Read more.
An experimental investigation focused on the manipulation of the wake generated by a square back car model is presented. Four continuously-blowing rectangular slot jets were mounted on the rear face of a 1:10 commercial van model. Load cell measurements evidence drag reduction for different forcing configurations, reaching a maximum of 12% for lateral and bottom jets blowing. The spectral analysis of the pressure fluctuations evidence, for all forced cases, an energy attenuation with respect to the natural case, especially close to the shedding frequency. An energy budget highlighted the most efficient forcing configurations accounting for both the drag reduction and the power required to feed the blowing system. Two main configurations are considered: the maximum drag reduction and the best compromise, yielding 5% drag reduction and a convenient energy balance. Particle Image Velocimetry (pPIV) and stereoscopic PIV (sPIV) experiments were performed allowing the three-dimensional reconstruction of the wake in the three considered configurations. Consistently with static and fluctuating pressure measurements, sPIV results reveal a dramatic change in the wake structure when the jets blow in the maximum drag reduction configuration. Conversely, the best compromise configuration reveals a wake structure similar to the natural one. Full article
(This article belongs to the Special Issue Flow and Aeroelastic Control)
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24 pages, 1701 KiB  
Article
Grid-Based and Polytopic Linear Parameter-Varying Modeling of Aeroelastic Aircraft with Parametric Control Surface Design
by Réka Dóra Mocsányi, Béla Takarics, Aditya Kotikalpudi and Bálint Vanek
Fluids 2020, 5(2), 47; https://doi.org/10.3390/fluids5020047 - 10 Apr 2020
Cited by 2 | Viewed by 2391
Abstract
The main direction of aircraft design today and in the future is to achieve more lightweight and higher aspect ratio airframes with the aim to improve performance and to reduce operating costs and harmful emissions. This promotes the development of flexible aircraft structures [...] Read more.
The main direction of aircraft design today and in the future is to achieve more lightweight and higher aspect ratio airframes with the aim to improve performance and to reduce operating costs and harmful emissions. This promotes the development of flexible aircraft structures with enhanced aeroelastic behaviour. Increased aeroservoelastic (ASE) effects such as flutter can be addressed by active control technologies. Control design for flutter suppression heavily depends on the control surface sizing. Control surface sizing is traditionally done in an iterative process, in which the sizing is determined considering solely engineering rules and the control laws are designed afterwards. However, in the case of flexible vehicles, flexible dynamics and rigid body control surface sizing may become coupled. This coupling can make the iterative process lengthy and challenging. As a solution, a parametric control surface design approach can be applied, which includes limitations of control laws in the design process. For this a set of parametric models is derived in the early stage of the aircraft design. Therefore, the control surfaces can be optimized in a single step with the control design. The purpose of this paper is to describe as well as assess the developed control surface parameterized ASE models of the mini Multi Utility Technology Testbed (MUTT) flexible aircraft, designed at the University of Minnesota. The ASE model is constructed by integrating aerodynamics, structural dynamics and rigid body dynamics. In order to be utilized for control design, control oriented, low order linear parameter-varying (LPV) models are developed using the bottom-up modeling approach. Both grid- and polytopic parametric LPV models are obtained and assessed. Full article
(This article belongs to the Special Issue Flow and Aeroelastic Control)
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29 pages, 4350 KiB  
Article
A Numerical Investigation of the Geometric Parametrisation of Shock Control Bumps for Transonic Shock Oscillation Control
by Jack A. Geoghegan, Nicholas F. Giannelis and Gareth A. Vio
Fluids 2020, 5(2), 46; https://doi.org/10.3390/fluids5020046 - 10 Apr 2020
Cited by 11 | Viewed by 3685
Abstract
At transonic flight conditions, shock oscillations on wing surfaces are known to occur and result in degraded aerodynamic performance and handling qualities. This is a purely flow-driven phenomenon, known as transonic buffet, that causes limit cycle oscillations and may present itself within the [...] Read more.
At transonic flight conditions, shock oscillations on wing surfaces are known to occur and result in degraded aerodynamic performance and handling qualities. This is a purely flow-driven phenomenon, known as transonic buffet, that causes limit cycle oscillations and may present itself within the operational flight envelope. Hence, there is significant research interest in the development of shock control techniques to either stabilise the unsteady flow or raise the boundary onset. This paper explores the efficacy of dynamically activated contour-based shock control bumps within the buffet envelope of the OAT15A aerofoil on transonic flow control numerically through unsteady Reynolds-averaged Navier–Stokes modelling. A parametric evaluation of the geometric variables that define the Hicks–Henne-derived shock control bump will show that bumps of this type lead to a large design space of applicable shapes for buffet suppression. Assessment of the flow field, local to the deployed shock control bump geometries, reveals that control is achieved through a weakening of the rear shock leg, combined with the formation of dual re-circulatory cells within the separated shear-layer. Within this design space, favourable aerodynamic performance can also be achieved. The off-design performance of two optimal shock control bump configurations is explored over the buffet region for M = 0.73, where the designs demonstrate the ability to suppress shock oscillations deep into the buffet envelope. Full article
(This article belongs to the Special Issue Flow and Aeroelastic Control)
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18 pages, 14364 KiB  
Article
Design and Optimization of an Aeroservoelastic Wind Tunnel Model
by Johannes K. S. Dillinger, Yasser M. Meddaikar, Jannis Lübker, Manuel Pusch and Thiemo Kier
Fluids 2020, 5(1), 35; https://doi.org/10.3390/fluids5010035 - 17 Mar 2020
Cited by 6 | Viewed by 3109
Abstract
Through the combination of passive and active load alleviation techniques, this paper presents the design, optimization, manufacturing, and update of a flexible composite wind tunnel model. In a first step, starting from the specification of an adequate wing and trailing edge flap geometry, [...] Read more.
Through the combination of passive and active load alleviation techniques, this paper presents the design, optimization, manufacturing, and update of a flexible composite wind tunnel model. In a first step, starting from the specification of an adequate wing and trailing edge flap geometry, passive, static aeroelastic stiffness optimizations for various objective functions have been performed. The second optimization step comprised a discretization of the continuous stiffness distributions, resulting in manufacturable stacking sequences. In order to determine which of the objective functions investigated in the passive structural optimization most efficiently complemented the projected active control schemes, the condensed modal finite element models were integrated in an aeroelastic model, involving a dedicated gust load alleviation controller. The most promising design was selected for manufacturing. The finite element representation could be updated to conform to the measured eigenfrequencies, based on the dynamic identification of the model. Eventually, a wind tunnel test campaign was conducted in November 2018 and results have been examined in separate reports. Full article
(This article belongs to the Special Issue Flow and Aeroelastic Control)
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16 pages, 4824 KiB  
Article
Full-Span Flying Wing Wind Tunnel Test: A Body Freedom Flutter Study
by Pengtao Shi, Jihai Liu, Yingsong Gu, Zhichun Yang and Pier Marzocca
Fluids 2020, 5(1), 34; https://doi.org/10.3390/fluids5010034 - 16 Mar 2020
Cited by 7 | Viewed by 3598
Abstract
Aiming at the experimental test of the body freedom flutter for modern high aspect ratio flexible flying wing, this paper conducts a body freedom flutter wind tunnel test on a full-span flying wing flutter model. The research content is summarized as follows: (1) [...] Read more.
Aiming at the experimental test of the body freedom flutter for modern high aspect ratio flexible flying wing, this paper conducts a body freedom flutter wind tunnel test on a full-span flying wing flutter model. The research content is summarized as follows: (1) The full-span finite element model and aeroelastic model of an unmanned aerial vehicle for body freedom flutter wind tunnel test are established, and the structural dynamics and flutter characteristics of this vehicle are obtained through theoretical analysis. (2) Based on the preliminary theoretical analysis results, the design and manufacturing of this vehicle are completed, and the structural dynamic characteristics of the vehicle are identified through ground vibration test. Finally, the theoretical analysis model is updated and the corresponding flutter characteristics are obtained. (3) A novel quasi-free flying suspension system capable of releasing pitch, plunge and yaw degrees of freedom is designed and implemented in the wind tunnel flutter test. The influence of the nose mass balance on the flutter results is explored. The study shows that: (1) The test vehicle can exhibit body freedom flutter at low airspeeds, and the obtained flutter speed and damping characteristics are favorable for conducting the body freedom flutter wind tunnel test. (2) The designed suspension system can effectively release the degrees of freedom of pitch, plunge, and yaw. The flutter speed measured in the wind tunnel test is 9.72 m/s, and the flutter frequency is 2.18 Hz, which agree well with the theoretical results (with flutter speed of 9.49 m/s and flutter frequency of 2.03 Hz). (3) With the increasing of the mass balance at the nose, critical speed of body freedom flutter rises up and the flutter frequency gradually decreases, which also agree well with corresponding theoretical results. Full article
(This article belongs to the Special Issue Flow and Aeroelastic Control)
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