International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / The Interactive Analysis and Display System (IADS) provides the structures flight test engineer with enhanced test-data processing, management, and display capabilities necessary to perform safety critical aircraft analysis in near real time during a flight test mission. Germane to hazardous, fast-paced flight test programs is a need for enhanced situational awareness in the Mission Control Room (MCR). The IADS provides an enhanced situational awareness by providing an analysis and display capability designed to enhance the confidence of the engineer in making clearance decisions within the MCR environment. The IADS will allow the engineer to achieve this confidence level by providing a real-time display capability along with a simultaneous near real-time processing capability consisting of both time domain and frequency domain analyses. The system provides for displaying real-time data while performing interactive and automated near real-time analyses. The system also alerts the engineer when displayed and non-displayed parameters exceed predefined threshold limits. Both real-time data and results created in near real-time may be compared to predicted data on workstations to enhance the user’s confidence in making point-to-point clearance decisions. The IADS also provides a post-flight capability at the engineers project area desktop. Having a user interface that is common with the real-time system, the post-flight IADS provides all of the capabilities of the real-time IADS plus additional data storage and data organization to allow the engineer to perform structural analysis with test data from the complete test program. This paper discusses the system overview and capabilities of the IADS.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The Interactive Analysis and Display System (IADS) provides the structures flight test engineer with enhanced test-data processing, management and display capabilities necessary to perform safety critical aircraft analysis in near real-time during a flight test mission. The IADS provides enhanced situational awareness through an analysis and display capability designed to increase the confidence of the engineer in making clearance decisions within the Mission control Room (MCR) environment. The engineer achieves this confidence level through IADS’ real-time display capability and simultaneous near real-time processing capability consisting of both time domain and frequency domain analyses. The system displays real-time data while performing interactive and automated near real-time analyses; alerting the engineer when displayed parameters exceed predefined threshold limits. Real-time data and results created in near real-time may be compared to previous flight test data to enhance the user’s confidence in making point-to-point clearance decisions. The IADS provides a post flight capability at the engineer’s project area desktop, with a user interface common with the real-time system. The post flight IADS provides all of the capabilities of the real-time IADS with additional data access and data organization, allowing the engineer to perform structural analysis with test data from the each flight and compile summary plots and tables over the most of the test program. The IADS promotes teamwork by allowing the engineers to share data and test results during a mission and in the post flight environment. This paper discusses the system overview and capabilities of the IADS.

This dissertation investigates the effect of airfoil steady loading on the sound generated by the interaction of an isolated, zero-thickness airfoil with a high-frequency convected disturbance. The analysis is based on a linearization of the inviscid equations of motion about a nonuniform mean flow. The mean flow is assumed to be two-dimensional and subsonic. Throughout most of the dissertation, we assume that the Mach number is 0(1), though in one section we concentrate on the leading-edge region and study the behavior of the sound field as the Mach number tends to zero. The small parameter representing the amount of airfoil camber and incidence angle, and the large parameter representing the ratio of airfoil chord to disturbance wavelength, are utilized in a singular perturbation analysis. The analysis shows that essentially all of the sound is generated at the leading and trailing edges, in regions the size of the disturbance wavelength. The solution in the local-leading-edge region reveals several sound-generating mechanisms which do not exist for an airfoil with no mean loading. These mechanisms are not present at the trailing edge; the trailing edge is important only as a scatterer of the sound produced at the leading edge. The propagation of sound away from the airfoil edges is described by geometric acoustics, with the amplitude varying on the scale of the airfoil chord and the phase varying on the much smaller scale of the disturbance wavelength. In addition, a diffraction-type transition region exists downstream of the airfoil. Calculations of radiated acoustic power show that the sound field depends strongly on Mach number, gust characteristics, and airfoil steady loading. Small changes in these properties can produce large changes in radiated power levels. Most importantly, we find that the amount of power radiated correlates very well with the strength of the mean flow around the leading edge.

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Thesis (M.S.)--Ohio State University, 1982. / Includes bibliographical references (leaves 56-59). Available online via OhioLINK's ETD Center.

Coastal bridges are exposed to severe wave, current and wind forces during a hurricane. Most coastal bridges are not designed to resist wave loads in such extreme situations, and there are no existing analytical methods to calculate wave loads on coastal highway bridges. This study focuses on developing a new scheme to estimate the extreme wave loads on bridges for designing purpose. In order to do this, a 2D wave velocity potential model (2D Model) is set up for the deterministic analysis of wave force on bridge decks. 2D Model is a linear wave model, which has the capability of calculating wave velocity potential components in time domain based on wave parameters such as wave height, wave period and water depth, and complex structural geometries. 2D Model has Laplace equation as general equation. The free surface boundary, incoming and outgoing wave boundary conditions are linearized, decomposed first, and then solved by the finite difference method. Maximum wave forces results calculated by the linear 2D Model are compared with results from CFD software Flow3D that is using Navier Stokes theory up to the 5th order; and 2D Model is validated by comparing results with experiment data. A case study is conducted for calculating extreme wave forces on I-10 Bridge across Escambia Bay, Florida during Hurricane Ivan in September 2004.SWAN model is adapted to investigate the parameters of wave heights and wave periods around bridge sites. SWAN model has the capability of predicting or hindcasting significant wave heights and wave periods as long as the domain and input parameters are given. The predicted significant wave heights are compared with measurements by Buoy Station 42039 and 42040 nearest to Escambia Bay. A new prediction equation of maximum uplift wave forces on bridge decks is developed in terms of wave height, wave period, water depth, bridge width, water clearance and over top water load. To develop the equations, the relationship is investigated between maximum uplift wave forces and wave parameters, water clearance, green water effects and bridge width. 2D Model is used for up to 1886 cases with difference parameters. Flow3D model is adopted to determine coefficients of water clearance and green water effects, which cannot be calculated by 2D Model.

Thesis (M.S.)--Oregon State University, 2003. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Deep foundations are commonly recommended when large displacements are expected. Typically, though, their design involves only checking and providing for sufficient capacity to carry the applied loads. Load-displacement behavior of piles is considered secondary to the axial capacity; displacements are ordinarily overlooked or not calculated if and when the estimated pile capacity is two to three times the design or expected loading. However, in cases, such as long piles or piles in dense cohesionless soils, displacements can be the critical factor in design or it could be a structural requirement to limit the displacements. In this dissertation, the displacements of axially loaded single piles are investigated by conducting analyses with the aid of an approach based on elasticity. The original solution predicting displacements due to a vertical load within a semi-infinite soil mass has been modified for varying soil conditions and layering, and assumptions of stresses and displacements acting on the soil-pile interface. Aside from the available/known factors of the pile (length, diameter, cross-sectional area, etc.) and the layering of the surrounding soil, Young's modulus and Poisson's ratio of the soil encompassing a pile are the unknowns required as input to obtain predictions based on the elastic method. In this study, attention is directed towards determining Young's modulus because the range and variability of Poisson's ratio is not significant in displacement calculations. Axial pile load testing data were provided by the California Department of Transportation as part of a project to improve its general approach to pile design. All of the tested piles were driven into the ground. Measurements of displacements and loads were made only at the top of the pile. Supplementary in-situ testing involving cone penetration (CPT) and standard penetration (SPT), drilling, and sample collection, were conducted in addition to laboratory testing to enhance the available information. In this research, predicted displacements are compared with those deduced from pile load tests. Two sets of predictions based on elastic method are conducted for comparing displacements. First, various correlations for Young's modulus are employed to determine how accurately each predicts the actual measured displacement. The chosen correlations utilize laboratory triaxial undrained shear strength and standard penetration test blowcount for cohesive and cohesionless soils, respectively. Secondly, the same data are also utilized to obtain back-calculated values of Young's moduli for analyses involving the elastic method. The measured displacements at loads of a third, a half, twothirds, and equal to the failure load were matched iteratively. Results from this research are deemed to have an impact on engineering practice by improving the determination of Young's modulus for displacement analyses involving the elastic method. A unique approach that has potential is the reconciliation of load ratios (percentage of failure load) with displacement calculations to provide a better overview of the range of load ratios for which these newly formulated correlations may be employed. Through this research, it is anticipated that better determination of soil parameters for elastic analysis of axial pile displacements can be made by researchers and engineers alike.