Wright-Patterson Air Force Base

About: Wright-Patterson Air Force Base is a other organization based out in Wright-Patterson AFB, Ohio, United States. It is known for research contribution in the topics: Laser & Mach number. The organization has 5817 authors who have published 9157 publications receiving 292559 citations. The organization is also known as: Wright-Patterson AFB & FFO.

An XPS study of cerium dopants in sol–gel coatings for aluminum 2024-T3

Abstract: Corrosion protection is a key requirement for coatings on aircraft as the US Air Force extends the lifetime of its fleet. Coating systems for aluminum have long incorporated chromates in conversion coatings to protect against corrosion, but environmental restrictions require that alternative coating systems be developed. Cerium has been proposed as an alternative to chromate inhibitors, as have several other rare earth elements, because the rare earths behave as cathodic inhibitors in aluminum. Epoxy silicate sol–gels, containing a few wt.% of cerium salts, were investigated as coatings on aluminum alloy 2024-T3. The salts used were cerium(III) chloride, cerium(III) nitrate hexahydrate, and ammonium cerium(IV) nitrate. X-Ray photoelectron spectroscopy (XPS/ESCA) was used to study both the doped sol–gels and reference cerium compounds in order to determine the oxidation state of the cerium at the surface of the sol–gel coatings. No change in the oxidation state of the cerium in the sol–gels was found. Coupled with electrical impedance spectroscopy measurements, the incorporation of cerium into sol–gels seems promising for future corrosion protection of aluminum 2024-T3.

A time‐implicit high‐order compact differencing and filtering scheme for large‐eddy simulation

Abstract: This work investigates a high-order numerical method which is suitable for performing large-eddy simulations, particularly those containing wall-bounded regions which are considered on stretched curvilinear meshes. Spatial derivatives are represented by a sixth-order compact approximation that is used in conjunction with a tenth-order non-dispersive filter. The scheme employs a time-implicit approximately factored finite-difference algorithm, and applies Newton-like subiterations to achieve second-order temporal and sixth-order spatial accuracy. Both the Smagorinsky and dynamic subgrid-scale stress models are incorporated in the computations, and are used for comparison along with simulations where no model is employed. Details of the method are summarized, and a series of classic validating computations are performed. These include the decay of compressible isotropic turbulence, turbulent channel flow, and the subsonic flow past a circular cylinder. For each of these cases, it was found that the method was robust and provided an accurate means of describing the flowfield, based upon comparisons with previous existing numerical results and experimental data. Published in 2003 by John Wiley & Sons, Ltd.

Approximate Stresses in an Orthotropic Plate Containing a Circular Hole

Abstract: An approximate solution in the form of a polynomial is presented for the normal stress distribution adjacent to a circular hole in an infinite orthotropic plate. Comparison of the approximate solut...

Structural optimization: A review and some recommendations

Abstract: A brief review of the structural optimization literature and a description of the present status of optimization methods are presented. The scope of the review is limited and does not profess to cover the entire literature. Results of the optimization of two structures (by the optimality criteria approach) are presented. There are some conclusions and recommendations for future developments in structural optimization.