2,416 research outputs found
Development of a computer code for calculating the steady super/hypersonic inviscid flow around real configurations. Volume 2: Code description
A numerical procedure was developed to compute the inviscid super/hypersonic flow field about complex vehicle geometries accurately and efficiently. A second-order accurate finite difference scheme is used to integrate the three-dimensional Euler equations in regions of continuous flow, while all shock waves are computed as discontinuities via the Rankine-Hugoniot jump conditions. Conformal mappings are used to develop a computational grid. The effects of blunt nose entropy layers are computed in detail. Real gas effects for equilibrium air are included using curve fits of Mollier charts. Typical calculated results for shuttle orbiter, hypersonic transport, and supersonic aircraft configurations are included to demonstrate the usefulness of this tool
Development of a computer code for calculating the steady super/hypersonic inviscid flow around real configurations. Volume 1: Computational technique
A numerical procedure has been developed to compute the inviscid super/hypersonic flow field about complex vehicle geometries accurately and efficiently. A second order accurate finite difference scheme is used to integrate the three dimensional Euler equations in regions of continuous flow, while all shock waves are computed as discontinuities via the Rankine Hugoniot jump conditions. Conformal mappings are used to develop a computational grid. The effects of blunt nose entropy layers are computed in detail. Real gas effects for equilibrium air are included using curve fits of Mollier charts. Typical calculated results for shuttle orbiter, hypersonic transport, and supersonic aircraft configurations are included to demonstrate the usefulness of this tool
Rotational Spectral Unmixing of Exoplanets: Degeneracies between Surface Colors and Geography
Unmixing the disk-integrated spectra of exoplanets provides hints about
heterogeneous surfaces that we cannot directly resolve in the foreseeable
future. It is particularly important for terrestrial planets with diverse
surface compositions like Earth. Although previous work on unmixing the spectra
of Earth from disk-integrated multi-band light curves appeared successful, we
point out a mathematical degeneracy between the surface colors and their
spatial distributions. Nevertheless, useful constraints on the spectral shape
of individual surface types may be obtained from the premise that albedo is
everywhere between 0 and 1. We demonstrate the degeneracy and the possible
constraints using both mock data based on a toy model of Earth, as well as real
observations of Earth. Despite the severe degeneracy, we are still able to
recover an approximate albedo spectrum for an ocean. In general, we find that
surfaces are easier to identify when they cover a large fraction of the planet
and when their spectra approach zero or unity in certain bands.Comment: 11 pages, 7 figures, published in AJ. Minor text updates from
previous versio
Hands On Painting
How can we know something through how it is sensed? Making anthropomorphic, three-dimensional paintings through a set of basic, at-hand materials, I’m interested in how empathy, modesty, and doubt can mediate a tangible experience of an object. Challenging notions of perception, I want to create a heightened sense of awareness in which the intangible can be seen or felt
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