Development and application of computational aerothermodynamics flowfield computer codes

Multiple nozzle plume flow field is computed with a 3-D, Navier-Stokes solver. Numerical simulation is performed with a flux-split, two-factor, time asymptotic viscous flow solver of Ying and Steger. The two factor splitting provides a stable 3-D solution procedure under ideal-gas assumptions. An ad-hoc acceleration procedure that shows promise in improving the convergence rate by a factor of three for steady state problems is utilized. Computed solutions to generic problems at various altitude and flight conditions show flow field complexity and three-dimensional effects due to multiple nozzle jet interactions. Viscous, ideal gas solutions for the symmetric nozzle are compared with other numerical solutions

The multidimensional self-adaptive grid code, SAGE

This report describes the multidimensional self-adaptive grid code SAGE. A two-dimensional version of this code was described in an earlier report by the authors. The formulation of the multidimensional version is described in the first section of this document. The second section is presented in the form of a user guide that explains the input and execution of the code and provides many examples. Successful application of the SAGE code in both two and three dimensions for the solution of various flow problems has proven the code to be robust, portable, and simple to use. Although the basic formulation follows the method of Nakahashi and Deiwert, many modifications have been made to facilitate the use of the self-adaptive grid method for complex grid structures. Modifications to the method and the simplified input options make this a flexible and user-friendly code. The new SAGE code can accommodate both two-dimensional and three-dimensional flow problems

Modularity and Innovation in Complex Systems

The problem of designing, coordinating, and managing complex systems has been central to the management and organizations literature. Recent writings have tended to offer modularity as, at least, a partial solution to this design problem. However, little attention has been paid to the problem of identifying what constitutes an appropriate modularization of a complex system. We develop a formal simulation model that allows us to carefully examine the dynamics of innovation and performance in complex systems. The model points to the trade-off between the destabilizing effects of overly refined modularization and the modest levels of search and a premature fixation on inferior designs that can result from excessive levels of integration. The analysis highlights an asymmetry in this trade-off, with excessively refined modules leading to cycling behavior and a lack of performance improvement. We discuss the implications of these arguments for product and organization design.

Mars Sample Return: Grand Challenge for EDL

A year ago, I gave a talk in anticipation of a Mars Sample Return effort at the 9th Ablation Workshop. Since then a lot has happened. "April of this year, after a year of study phase, NASA and ESA (European Space Agency) signed a Statement of Intent (SOI) to jointly develop a Mars Sample Return plan to be submitted to their respective authorities by the end of 2019. This signing is historic, as it signals the desire, the readiness, and the willingness to work together to execute this inspiring mission, we all have the opportunity to tackle this grand challenge. We have the scientific and engineering maturity to identify the critical technologies ready to be applied, and with discipline this campaign can be executed affordably," Jim Watzin, Mars Program Executive, NASA. NASA Centers with JPL (Jet Propulsion Laboratory) leading the charge is in the midst of a pre-formulation phase for executing a Mars Sample Return before the end of next decade. The proposed talk builds on the previous year talk. In light of the agreement between NASA and ESA, NASA has assumed the responsibilities for developing the earth entry vehicle (EEV) that will fly along with a European Spacecraft and return with the sample from Mars. EEV will be deployed for entry into earth. The EEV design, development, testing and certification have to result in a highly reliable sample return system. The entire architecture has to be demonstrated to meet the planetary protection requirement. NASA is considering two distinctly different earth entry vehicle architectures and with each choice, many different ablative TPS (Thermal Protective Shield) candidates. As a result of the NASA-ESA ongoing studies, some of the key entry conditions and design requirements are better understood today and more are being scoped out. The heat-shield ablative TPS choice need to be done with a good understanding as it plays a very significant role in determining the robustness of the EEV. Knowledge about how materials and system perform, and how the features could become flaws and how flaws lead to failure, etc. need to be clearly understood and the knowledge then need to be used to down select the TPS. This proposed talk will provide greater insight into the progress being made and the challenges that need to be tackled

Mars Sample Return: Grand Challenge for EDL

No abstract availabl

Aesthetic Citizenship: Popular Culture, Migrant Youth, and the Making of \u27World Class\u27 Delhi

Delhi has nearly doubled in population since the early 1990s due to in-migration (censusindia.gov, 2011). These migrants, like migrants around the world, strive to adapt to their new surroundings by producing themselves in ways which make them socially, economically, and politically viable. My project examines how recent international and intranational immigrant youth who have come to Delhi to partake in its economic possibilities and, in some cases, to escape political uncertainty, are utilizing globally circulating popular cultural forms to make themselves visible in a moment when the city strives to recast its image as a world class destination for roaming capital (Roy, 2011). I focus on two super diverse settlement communities in South Delhi to explore the citizenship making claims of immigrant youth who, to date, have been virtually invisible in academic and popular narratives of the city. Specifically, I follow three groups of ethnically diverse migrant youth from these two settlement communities as they engage with hip hop, a popular cultural form originating in Black American communities in the 1970s (Chang, 2006; Morgan, 2009; Rose, 1994). As hip hop\u27s music and its practices gain popularity amongst youth in Delhi from across a wide spectrum of class and ethnic positions, I trace how these migrant youth utilize its styles and globally reaching networks coupled with inexpensive digital capture technology to fashion themselves and their settlement communities as part of a world class urbanity in the making.

Development and application of computational aerothermodynamics flowfield computer codes

Computations are presented for one-dimensional, strong shock waves that are typical of those that form in front of a reentering spacecraft. The fluid mechanics and thermochemistry are modeled using two different approaches. The first employs traditional continuum techniques in solving the Navier-Stokes equations. The second-approach employs a particle simulation technique (the direct simulation Monte Carlo method, DSMC). The thermochemical models employed in these two techniques are quite different. The present investigation presents an evaluation of thermochemical models for nitrogen under hypersonic flow conditions. Four separate cases are considered. The cases are governed, respectively, by the following: vibrational relaxation; weak dissociation; strong dissociation; and weak ionization. In near-continuum, hypersonic flow, the nonequilibrium thermochemical models employed in continuum and particle simulations produce nearly identical solutions. Further, the two approaches are evaluated successfully against available experimental data for weakly and strongly dissociating flows

PHYTOCHEMICAL SCREENING, ANTIOXIDANT ACTIVITY AND EXTRACTION OF ACTIVE COMPOUND (ANONAINE) FROM FRUIT PEEL EXTRACT OF ANNONA RETICULATA L.

Objective: The main objective of this study was to analyze the phytochemical constituents, total phenol, total flavonoid, alkaloid content, in vitro antioxidant activity and high-performance liquid chromatography (HPLC) analysis of anonaine compound from the fruit peel extract of Annona reticulata L.Methods: Preliminary phytochemical analysis for alkaloids, cardiac glycosides, flavonoids, glycosides, phenols, saponins, steroids, tannins, and terpenoids was studied. Quantitative phytochemical analysis for total phenolics, total flavonoids and alkaloids was determined according to standard protocols. In vitro antioxidant potential was evaluated by assessing 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity by following standard procedure. HPLC analysis was carried out to identify a major metabolite, namely, anonaine compound from fruit peel extract of A. reticulata L.Results: Phytochemical screening of various extracts such as aqueous, ethanol, chloroform, acetone, and petroleum ether of fruit peel extracts revealed the presence of tannins, saponins, phenols, flavonoids, cardiac glycosides, coumarins, terpenoids, alkaloids, and steroids. Total phenol, flavonoid and alkaloid contents were quantitatively estimated which recorded maximum in Ooty accession (17.75±0.13 mg gallic acid equivalents/g, 13.97±0.21 mg quercetin equivalents/g, and alkaloid content of 6.92±0.14 mg/g), respectively. Among three accessions with five different solvents used, maximum antioxidant activity was found in aqueous peel extract (90.76±1.3%) from Ooty accession followed by others. The results of HPLC analysis in the fruit peel extract of A. reticulata proved the presence of the active principle, namely anonaine compound.Conclusion: Therefore, this study suggests the possibility of using fruit peel extracts of A. reticulata as a potent source of natural antioxidant and thus could prevent many free radical mediated diseases. The validated HPLC method can be used for routine quality control analysis

Development and application of computational aerothermodynamics flowfield computer codes

Research was performed in the area of computational modeling and application of hypersonic, high-enthalpy, thermo-chemical nonequilibrium flow (Aerothermodynamics) problems. A number of computational fluid dynamic (CFD) codes were developed and applied to simulate high altitude rocket-plume, the Aeroassist Flight Experiment (AFE), hypersonic base flow for planetary probes, the single expansion ramp model (SERN) connected with the National Aerospace Plane, hypersonic drag devices, hypersonic ramp flows, ballistic range models, shock tunnel facility nozzles, transient and steady flows in the shock tunnel facility, arc-jet flows, thermochemical nonequilibrium flows around simple and complex bodies, axisymmetric ionized flows of interest to re-entry, unsteady shock induced combustion phenomena, high enthalpy pulsed facility simulations, and unsteady shock boundary layer interactions in shock tunnels. Computational modeling involved developing appropriate numerical schemes for the flows on interest and developing, applying, and validating appropriate thermochemical processes. As part of improving the accuracy of the numerical predictions, adaptive grid algorithms were explored, and a user-friendly, self-adaptive code (SAGE) was developed. Aerothermodynamic flows of interest included energy transfer due to strong radiation, and a significant level of effort was spent in developing computational codes for calculating radiation and radiation modeling. In addition, computational tools were developed and applied to predict the radiative heat flux and spectra that reach the model surface