2,616 research outputs found
Kara Gust interviews author Jeff Vande Zande
No full textAuthor Jeff Vande Zande talks about teaching and writing, poems vs. short stories, developing characters in his stories based on his personal experience, and his current projects. Vande Zande is interviewed by Michigan State University Librarian Kara Gust for the MSU Libraries' Michigan Writer Series
Kara Gust interviews author and bioregionalist Stephanie Mills
No full textAuthor and ecologist Stephanie Mills talks about how she started writing and publishing, writing on nature and the environment, the challenges of being a writer, the influence of Michigan on her work, bio-regionalism, and a new book she is working on. Mills is interviewed by Michigan State University Librarian Kara Gust for the Michigan State University Libraries' Michigan Writers Series
Gust response: a validation experiment and preliminary numerical simulations
No full textIn this paper the experimental setup and first results for a gust generator experiment will be presented. The experiment was carried out in the transonic wind-tunnel
facility in Goettingen (DNW-TWG). The first goal of the experiment was to answer the question, whether it is possible to induce an unsteady flow field with a rigid moving profile as a gust generator. Furthermore the main objective of the experiment was the understanding of the physical phenomena of an impacting gust on an elastic structure. For that purpose a new set-up has been constructed and built, which allows the investigation of two subsequent airfoil-models in the flow of the wind tunnel. The first airfoil is active and should produce a generic gust. The second model located downstream is passive and responds to the unsteady
load changes induced by the moving active profile. For a first investigation, amplitudes and frequencies were varied as well as the vertical position of both airfoils relative to each other. The experiment was conducted to deliver a comprehensive data base for validating the DLR in-house fluid-structure-interaction software “PyCSM” which has been developed for aeroelastic simulations in time domain.
In order to support the experiment in the preparation phase, fluid-structure-interaction simulations in time domain have been carried out. These simulations mainly show the response amplitudes expected for the passive wing. For that purpose the DLR TAU Code for the calculation of the steady and unsteady aerodynamic loads and a finite element shell
model have been used
Kara Gust interviews prolific author and poet, retired Michigan State University Professor Hugh B. Fox
No full textProlific author and poet, retired Michigan State University Professor Hugh B. Fox talks about his early family life in Chicago and his writing career. Fox explains how he became acquainted with theater, music, and ballet at a young age and how he was forced into medical school, but later abandoned it to pursue the liberal arts and writing. Fox talks about his many interests including archeology, and his treatise on author and friend Charles Bukowski. Fox is interviewed by Kara Gust for the Michigan State University Libraries' Michigan Writers Series
The effect of wavy leading edges on aerofoil-gust interaction noise
No full textHigh-order accurate numerical simulations are performed to investigate the effects of wavy leading edges (WLEs) on aerofoil–gust interaction (AGI) noise. The present study is based on periodic velocity disturbances predominantly in streamwise and vertical directions that are mainly responsible for the surface pressure fluctuation of an aerofoil. In general, the present results show that WLEs lead to reduced AGI noise. It is found that the ratio of the wavy leading-edge peak-to-peak amplitude (LEA) to the longitudinal wavelength of the incident gust (?g) is the most important factor for the reduction of AGI noise. It is observed that there exists a tendency that the reduction of AGI noise increases with LEA/?g and the noise reduction is significant for LEA/?g?0.3. The present results also suggest that any two different cases with the same LEA/?g lead to a strong similarity in their profiles of noise reduction relative to the straight leading-edge case. The wavelength of wavy leading edges (LEW), however, shows minor influence on the reduction of AGI noise under the present gust profiles used. Nevertheless, the present results show that a meaningful improvement in noise reduction may be achieved when 1.0?LEW/?g?1.5. In addition, it is found that the beneficial effects of WLEs are maintained for various flow incidence angles and aerofoil thicknesses. Also, the WLEs remain effective for gust profiles containing multiple frequency components. It is discovered in this paper that WLEs result in incoherent response time to the incident gust across the span, which results in a decreased level of surface pressure fluctuations, hence a reduced level of AGI noise
Kara Gust interviews author Ilana Blumberg
No full textProfessor Ilana Blumberg talks about becoming interested in reading and writing, her Jewish upbringing, and being a typical "American girl". She mentions the tensions of navigating between tradition and modernity and the special challenge for women that it poses. Blumberg also talks about how living in Michigan has influenced her writing and how she likes to write about families and the tensions of belonging while trying to find independence. Blumberg is interviewed by Kara Gust for the Michigan State University Libraries' Michigan Writers Series
High-order computations on aerofoil-gust interaction noise and the effects of wavy leading edges
No full textHigh-order accurate numerical simulations are performed to investigate the effects of wavy leading edges on aerofoil gust interaction (AGI) noise. The present study is based on periodic velocity dis-turbances predominantly in streamwise (x-) and vertical (y-) directions that are mainly responsible for the surface pressure fluctuation of an aerofoil. The perturbed velocity components of the present gust model do not vary in the spanwise (z-) direction. In general, the present results show that wavy leading edges lead to reduced AGI noise. Under the current incident gusts, it is found that the ratio of the wavy leading-edge peak-to-peak amplitude (LEA) to the longitudinal wavelength of the incident gust (?g) is the most important factor for the reduction of AGI noise. It is observed that AGI noise reduces with increasing LEA/?g, and significant noise reduction can be achieved for LEA/?g?0.3. The present results also suggest that any two different cases with the same LEA/?g lead to a strong similarity in their profiles of noise reduction relative to the straight leading-edge case. The wavelength of wavy leading edges (LEW), however, shows minor influence on the reduction of AGI noise under the present gust profiles used. Nevertheless, the present results show that a meaningful improvement in noise reduction may be achieved when 1.06LEW/?g 61.5. In addition, it is found that the beneficial effects of wavy leading edges are maintained for various angles of attack and aerofoil thicknesses. Also, wavy leading edges remain effective in reducing AGI noise for gust profiles containing multiple frequency components. It is discovered in the current research that wavy leading edges result in in-coherent response time to the incident gust across the span, which causes a decreased level of surface pressure fluctuations, hence a reduced level of AGI noise
An adaptive aeroelastic control approach using non linear reduced order models
No full textA systematic approach to the model order reduction of high fidelity coupled fluid/structure/flight dynamics models and the subsequent control design is described. It uses information on the eigenspectrum of the coupled-system Jacobian matrix and projects the system through a series expansion onto a small basis of eigenvectors representative of the full-model dynamics. A nonlinear reduced order model is derived and is exploited for a worst case gust and adaptive control design. The investigation focuses on a flight control design based on the model reference adaptive control scheme via the Lyapunov stability approach. The novelty of this paper is two-fold. Firstly, it uses a single nonlinear reduced model for parametric worst case gust search. Secondly, it is shown that it makes feasible an implementation of a complex control methodology for a large nonlinear system. The adaptive controller is able to alleviate gust loads for a three degrees-of-freedom aerofoil and for an unmanned aerial vehicle. An investigation for the adaptation parameters is performed and their effect on control input actuation and aeroelastic closed-loop response is discussed
Robust Control Synthesis for Gust Load Alleviation from Large Aeroelastic Models with Relaxation of Spatial Discretisation
No full text04/03/14 meb. Ok to add, authors retain copyright.This paper introduces a methodology for the design of gust load control systems directly from large aeroelastic models with relaxation of spatial discretisation. A convenient state-space representation of the vortex-panel unsteady aerodynamics suitable for control synthesis is presented. This allows a full understanding of the dynamics of the linearized vortex aeroelastic model and is suitable for control system design. Through the use of robust controllers, large reductions in loading could be achieved. Comparisons are also made between robust and classical control methods. It further demonstrates that controllers synthesized from models of coarse spatial discretizations and of an order of magnitude smaller in size were capable of rejecting disturbances on fully converged models, with performances comparable to expensive higher order controllers developed from full models
Predictive Control for Alleviation of Gust Loads on Very Flexible Aircraft
No full text11/03/14 meb. Author retains copyright as beforeIn this work the dynamics of very flexible aircraft are described by a set of non-linear, multi-disciplinary equations of motion. Primary structural components are represented by a geometrically-exact composite beam model which captures the large dynamic deformations of the aircraft and the interaction between rigid-body and elastic degrees-of-freedom. In addition, an implementation of the unsteady vortex-lattice method capable of handling arbitrary kinematics is used to capture the unsteady, three-dimensional flow-eld around the aircraft as it deforms. Linearization of this coupled nonlinear description, which can in general be about a nonlinear reference state, is performed to yield relatively high-order linear time-invariant state-space models. Subsequent reduction of these models using standard balanced truncation results in low-order models suitable for the synthesis of online, optimization-based control schemes that incorporate actuator constraints. Predictive controllers are synthesized using these reduced-order models and applied to nonlinear simulations of the plant dynamics where they are shown to be superior to equivalent optimal linear controllers (LQR) for problems in which constraints are active
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