This paper describes the history, objectives, structure, and current capabilities of the Stanford University Unstructured (SU 2) tool suite. This computational analysis and design software collection is being developed to solve complex, multi-physics analysis and optimization tasks using arbitrary unstructured meshes, and it has been designed so that it is easily extensible for the solution of Partial Differential Equation-based (PDE) problems not directly envisioned by the authors. At its core, SU 2 is an open-source collection of C++ software tools to discretize and solve problems described by PDEs and is able to solve PDE-constrained optimization problems, including optimal shape design. Although the toolset has been designed with Computational Fluid Dynamics (CFD) and aerodynamic shape optimization in mind, it has also been extended to treat other sets of governing equations including potential flow, electrodynamics, chemically reacting flows, and several others. In our experience, capabilities for computational analysis and optimization have improved considerably over the past two decades. However, the ability to integrate the resulting software packages into coupled multi-physics analysis and design optimization solvers has remained a challenge: the variety of approaches chosen for the independent components of the overall problem (flow solvers, adjoint solvers, optimizers, shape parameterization, shape deformation, mesh adaption, mesh deformation, etc) make it difficult to (a) expand the range of applicability to situations not originally envisioned, and (b) to reduce the overall burden of creating integrated applications. By leveraging well-established object-oriented software architectures (using C++) and by enabling a common interface for all the necessary components, SU 2 is able to remove these barriers for both the beginner and the seasoned analyst. In this paper we attempt to describe our efforts to develop SU 2 as an integrated platform. In some senses, the paper can also be used as a software reference manual for those who might be interested in modifying it to suit their own needs. We carefully describe the C++ framework and object hierarchy, the sets of equations that can be currently modeled by SU 2 , the available choices for numerical discretization, and conclude with a set of relevant validation and verification test cases that are included with the SU 2 distribution. We intend for SU 2 to remain open source and to serve as a starting point for new capabilities not included in SU 2 today, that will hopefully be contributed by users in both academic and industrial environments.

SUAVE, a conceptual level aircraft design environment, incorporates multiple information sources to analyze unconventional configurations. Developing the capability of producing credible conceptual level design conclusions for futuristic aircraft with advanced technologies is a primary directive. Many software tools for aircraft conceptual design rely upon empirical correlations and other handbook approximations. SUAVE proposes a way to design aircraft featuring advanced technologies by augmenting relevant correlations with physics-based methods. SUAVE is constructed as a modular set of analysis tools written compactly and evaluated with minimal programming effort. Additional capabilities can be incorporated using extensible interfaces and prototyped with a top-level script. The flexibility of the environment allows the creation of arbitrary mission profiles, unconventional propulsion networks, and right-fidelity at right-time discipline analyses. This article will first explain how SUAVE's analysis capabilities are organized to enable flexibility. Then, it will summarize the analysis strategies for the various disciplines required to evaluate a mission. Of particular interest will be the construction of unconventional energy networks necessary to evaluate configurations such as hybrid-electric commercial transports and solar-electric unmanned aerial vehicles (UAVs). Finally, verification and validation studies will be presented to demonstrate the capabilities of SUAVE, including cases for conventional and unconventional vehicles. While some of these cases will be optimized results, discussion of SUAVE's interface with optimization will be reserved for a future publication.

We report near-infrared photometry, spectroscopy, and speckle imaging of the hot, luminous star we identify as candidate LBV 1806-20 1 . We also present photometry and spectroscopy of 3 nearby stars, which are members of the same star cluster containing LBV 1806-20 and SGR 1806-20. The spectroscopy and photometry show that LBV 1806-20 is similar in many respects to the luminous 1 Based on data obtained with the Cerro Tololo Interamerican Observatory 4-meter telescope operated by NOAO. NOAO is operated by the Association of Universities for Research in Astronomy (AURA), Inc. under cooperative agreement with the National Science Foundation.

We report the discovery of a bright (J = 13.83±0.03) methane brown dwarf, or T dwarf, by the Two Micron All Sky Survey. This object, 2MASSI J0559191-140448, is the first brown dwarf identified by the newly commissioned CorMASS instrument mounted on the Palomar 60-inch Telescope. Near-infrared spectra from 0.9 -2.35 µm show characteristic CH 4 bands at 1.1, 1.3, 1.6, and 2.2 µm, which are significantly shallower than those seen in other T dwarfs discovered to date. Coupled with the detection of an FeH band at 0.9896 and two sets of K I doublets at J-band, we propose that 2MASS J0559-14 is a warm T dwarf, close to the transition between L and T spectral classes. The brightness of this object makes it a good candidate for detailed investigation over a broad wavelength regime and at higher resolution.

This article presents a review of key historical contributions, the current status, and future research avenues in support of the development of supersonic aircraft that are sufficiently quiet so that they can be allowed to fly supersonically over land. For this goal to be achievable, in addition to overcoming many other challenges in aerodynamics, structures, propulsion, acoustics, and aeroservoelasticity, the pressure signature created by the aircraft must be such that, when it reaches the ground, (a) it can barely be perceived by the human ear, and (b) it results in disturbances to man-made structures that do not exceed the threshold of annoyance for a significant percentage of the population. In other words, the ground-boom signature must meet a number of key constraints that can be appropriately quantified. In designing aircraft with low sonic booms, it is important to understand (a) how pressure disturbances are generated and how they propagate through the atmosphere, (b) under which conditions will the pressure signature created by an aircraft evolve to generate an acceptable low-boom signature at the ground, and (c) what multidisciplinary trade-offs need to be made to realize low-boom aircraft that are also economically and environmentally compliant. This article discusses each of these areas separately, assesses the accomplishments in each topic, identifies significant shortcomings, and suggests future research efforts (some already ongoing) that have the potential to yield solutions to all these issues.