1,721,314 research outputs found
Dataset supporting the publication "Effects of integral length scale variations on the stall characteristics of a wing at high freestream turbulence conditions"
No full textThis dataset is supporting the publication "Effects of integral length scale variations on the stall characteristics of a wing at high freestream turbulence conditions". To be published in Journal of Fluid Mechanics
This dataset includes all the relevant data for the figures found within the paper in txt format.
For enquiries please contact Craig Thompson: [email protected]</span
Image of Hollis Thompson, Craig Holmgren, and Chad Holmgren stacking hay, circa 1980.
No full textHollis Thompson, Craig Holmgren, and Chad Holmgren stacking hay at the Connor Springs Ranch, circa 1980
A comprehension and prediction of wings in unsteady conditions
No full textThis thesis presents experimental and computational work that explores the complex dynamics of rigid and aeroelastic wings under the influence of unsteady, turbulent flow conditions pre and post-stall. Such conditions are increasingly relevant to modern aerospace applications, where understanding and predicting the behaviour of wings can significantly enhance aircraft performance and safety.The study focuses on the impact of varying the integral length scale on the aerodynamic performance of wings at moderate Reynolds numbers. Through experimental investigations using hot wire anemometry, force and moment measurements, particle image velocimetry, and digital image correlation, detailed insights into the response of rigid and aeroelastic wings alongside their surrounding flow fields are obtained. In particular, the dynamics of variations in the integral length scale of high-intensity free-stream turbulence are investigated. This thesis also incorporates data assimilation techniques to refine the predictions of flow behaviour around stalled airfoils subjected to free-stream turbulence. Specifically focusing on the application of data assimilation to high Reynolds number time-averaged flows, and investigating the scaling behaviour for different Reynolds numbers and turbulence intensities.Key findings from this research include the identification of peak force fluctuations for the rigid wing at integral length scales equal to half the wing's chord and how these scales influence vortex shedding and stall characteristics. For aeroelastic wings, the interaction between structural responses (bending, torsion and surge) and turbulent flow reveals that varying the integral length scale of the incoming turbulence leads to the preferential amplification of certain frequencies over others.The thesis advances the application of a state observer method to enhance the accuracy of existing turbulence models. The method is capable of improving results where experimental data is known for a range of Reynolds numbers and turbulence intensities. Additionally, by scaling the forcing term or inlet conditions, the method accurately predicts flows where experimental data is unknown
Rigid and flexible wings subject to large intensity turbulence
No full textA rigid and flexible wing with NACA0012 profile was subjected to clean and turbulent conditions. The deformation of the flexible wing was studied in the clean flow condition using digital image correlation. Turbulent conditions generated by an active grid included turbulence intensities and integral length scales spanning from Tu = 9.5 % to 19.6 % and Lx = 0.14 m to 0.33 m respectively. A 6-axis load cell was used to measure the forces and moments generated by both wings in all flow conditions. The onset of stall was delayed with the introduction of free stream turbulence and similarly the peak time averaged lift coefficient increased, however at large intensities this improvement began to diminish. A comparison between the turbulent length scale and excitation of particular structural modes in the flexible wing were observed, sharing similarities with previous studies involving flexible wings in harmonic gusts.</p
Aeroelastic wing performance in high intensity turbulence: integral length scale effects
No full textThe impact of variations in the integral length scale of incoming free-stream turbulence onan aeroelastic NACA0012 wing is investigated using force, moment and PIV measurements. Ata chord-based Reynolds number
Dataset supporting the publication "The effect of variations in experimental and computational fidelity on data assimilation approaches"
No full textDataset supporting the publication "The effect of variations in experimental and computational fidelity on data assimilation approaches" by C. Thompson, U. Cadambi Padmanaban, B. Ganapathisubramani and S. Symon, in TCFD journal, DOI: 10.1007/s00162-024-00708-y
This dataset includes the data and codes for the above manuscript. The data is presented in a zipped file: TCFD_open_data.zip
most data is presented in .dat format named after the figures that were developed from this data.
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The effect of variations in experimental and computational fidelity on data assimilation approaches
No full textWe conduct a comprehensive analysis of two data assimilation methods: the first utilizes the discrete adjoint approach with a correction applied to the production term of the turbulence transport equation, preserving the Boussinesq approximation. The second is a state observer method that implements a correction in the momentum equations alongside a turbulence model, both applied to fluid dynamics simulations. We investigate the impact of varying computational mesh resolutions and experimental data resolutions on the performance of these methods within the context of a periodic hill test case. Our findings reveal the distinct strengths and limitations of both methods, which successfully assimilate data to improve the accuracy of a RANS simulation. The performance of the variational model correction method is independent of input data and computational mesh resolutions. The state observer method, on the other hand, is sensitive to the resolution of the input data and CFD mesh
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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