Tetrahedral Finite-Volume Solutions to the Navier-Stokes Equations on Complex Configurations

A review of the algorithmic features and capabilities of the unstructured-grid flow solver USM3Dns is presented. This code, along with the tetrahedral grid generator, VGRIDns, is being extensively used throughout the U.S. for solving the Euler and Navier-Stokes equations on complex aerodynamic problems. Spatial discretization is accomplished by a tetrahedral cell-centered finite-volume formulation using Roe's upwind flux difference splitting. The fluxes are limited by either a Superbee or MinMod limiter. Solution reconstruction within the tetrahedral cells is accomplished with a simple, but novel, multidimensional analytical formula. Time is advanced by an implicit backward-Euler time-stepping scheme. Flow turbulence effects are modeled by the Spalart-Allmaras one-equation model, which is coupled with a wall function to reduce the number of cells in the near-wall region of the boundary layer. The issues of accuracy and robustness of USM3Dns Navier-Stokes capabilities are addressed for a flat-plate boundary layer, and a full F-16 aircraft with external stores at transonic speed

Status of VGRID/USM3D aero analysis system

The topics are presented in viewgraph form and include the following: grid generation; flow solver; graphic postprocessing; dissemination; customer applications; and plans

An unstructured-grid software system for solving complex aerodynamic problems

A coordinated effort has been underway over the past four years to elevate unstructured-grid methodology to a mature level. The goal of this endeavor is to provide a validated capability to non-expert users for performing rapid aerodynamic analysis and design of complex configurations. The Euler component of the system is well developed, and is impacting a broad spectrum of engineering needs with capabilities such as rapid grid generation and inviscid flow analysis, inverse design, interactive boundary layers, and propulsion effects. Progress is also being made in the more tenuous Navier-Stokes component of the system. A robust grid generator is under development for constructing quality thin-layer tetrahedral grids, along with a companion Navier-Stokes flow solver. This paper presents an overview of this effort, along with a perspective on the present and future status of the methodology

Project and production management Intersection: Life-Cycle analysis of on-site and off-site construction

The purpose of this paper is to provide an argument for moving beyond calls for increased construction industry productivity based on the perceived differences between construction projects and manufacture production. Traditionally scholars have claimed that the lack of increased construction industry productivity is attributable to the differences between on-site work and off-site work. However, in 2011 project processes and product outcomes are essential to both. As management theories have become integrated into practice in both industries, the management of both a unique project and product-production have converged. At the same time, almost all construction today utilises both on-site and off-site processes. Therefore, the driver for increased off-site manufacture to ensure increased industry productivity must be reconsidered. One way forward would be to consider issues related to reducing the environmental impacts of construction. That is the aim of this discussion paper. Many researchers have identified difficulties with communication between on-site and off-site production. However, if the focus of productivity gains shifts to measuring environmental impact, based on a Life-Cycle Analysis (LCA), then both the tangible and intangible effects of both on-site and off-site work can be compared. Thus, over-coming identified difficulties with a common language based on LCA could enable co-operative on and off site production. This co-operation could in turn to lead to increased industry productivity. The paper ends by providing a LCA focused research agenda to provide evidence for reconsidering the claim that increasing off-site manufacture will increase construction industry productivity

CFD Assessment of Aerodynamic Degradation of a Subsonic Transport Due to Airframe Damage

A computational study is presented to assess the utility of two NASA unstructured Navier-Stokes flow solvers for capturing the degradation in static stability and aerodynamic performance of a NASA General Transport Model (GTM) due to airframe damage. The approach is to correlate computational results with a substantial subset of experimental data for the GTM undergoing progressive losses to the wing, vertical tail, and horizontal tail components. The ultimate goal is to advance the probability of inserting computational data into the creation of advanced flight simulation models of damaged subsonic aircraft in order to improve pilot training. Results presented in this paper demonstrate good correlations with slope-derived quantities, such as pitch static margin and static directional stability, and incremental rolling moment due to wing damage. This study further demonstrates that high fidelity Navier-Stokes flow solvers could augment flight simulation models with additional aerodynamic data for various airframe damage scenarios

In vitro activities of tetracyclines against different clones of multidrug-resistant Acinetobacter baumannii isolates from two Iranian hospitals.

Acinetobacter baumannii has emerged as one of the most challenging healthcare-related pathogens and its occurrence has increased worldwide, especially in patients admitted to intensive care units. A. baumannii isolates are frequently resistant to multiple antimicrobial agents and there are recent reports of isolates resistant to virtually all clinically relevant drugs. In the present study, the in vitro activities of tigecycline, minocycline and doxycycline against 67 MDR-AB isolates recovered from 29 burn and 38 non-burn Iranian patients hospitalised in Tehran and Tabriz, respectively, were studied. Tigecycline and minocycline may be still considered effective therapeutic options for MDR-AB infections. However, ongoing monitoring of A. baumannii susceptibility to these antibiotics is required

Implementation of Flow Tripping Capability in the USM3D Unstructured Flow Solver

A flow tripping capability is added to an established NASA tetrahedral unstructured parallel Navier-Stokes flow solver, USM3D. The capability is based on prescribing an appropriate profile of turbulence model variables to energize the boundary layer in a plane normal to a specified trip region on the body surface. We demonstrate this approach using the k-e two-equation turbulence model of USM3D. Modification to the solution procedure primarily consists of developing a data structure to identify all unstructured tetrahedral grid cells located in the plane normal to a specified surface trip region and computing a function based on the mean flow solution to specify the modified profile of the turbulence model variables. We leverage this data structure and also show an adjunct approach that is based on enforcing a laminar flow condition on the otherwise fully turbulent flow solution in user specified region. The latter approach is applied for the solutions obtained using other one- and two-equation turbulence models of USM3D. A key ingredient of the present capability is the use of a graphical user-interface tool PREDISC to define a trip region on the body surface in an existing grid. Verification of the present modifications is demonstrated on three cases, namely, a flat plate, the RAE2822 airfoil, and the DLR F6 wing-fuselage configuration

Construction hazard prevention: The need to integrate process knowledge into product design

Social network analysis was used to model information exchange networks in construction case studies in the United States of America and Australia/New Zealand. For each case, the quality of work safety and health (WHS) risk control outcomes was measured. This measurement was based on an established "hierarchy of control" in which risk controls are classified in descending order of effectiveness. The construction contractors' degree centrality was examined as a proxy measure of the constructors' influence in decision making during the pre-construction stages of the project. Network metrics were compared for cases in which the risk control scores were higher and lower than average. The results showed a significant difference in constructors' degree centrality for cases with high and low risk control efficacy scores. Constructors had significantly higher degree centrality in cases with high compared to low quality OSH risk control outcomes. The results provide preliminary evidence that integrating construction process knowledge into pre-construction decision-making produces better OSH outcomes. The research also highlights the potential usefulness of social network analysis and network metrics in OSH performance measurement and benchmarking

Designer Magnetoplasmonics with Nickel Nanoferromagnets

We introduce a new perspective on magnetoplasmonics in nickel nanoferromagnets by exploiting the phase tunability of the optical polarizability due to localized surface plasmons and simultaneous magneto-optical activity. We demonstrate how the concerted action of nanoplasmonics and magnetization can manipulate the sign of rotation of the reflected light’s polarization (i.e., to produce Kerr rotation reversal) in ferromagnetic nanomaterials and, further, how this effect can be dynamically controlled and employed to devise conceptually new schemes for biochemosensing. © 2011 American Chemical Society.A.D. and Z.P. acknowledge support from the Swedish Research Council and Swedish Foundation for Strategic Research (Framework program Functional Electromagnetic Metamaterials, project RMA08). J.Å. acknowledges support from the Swedish Research Council, the Swedish Foundation for Strategic Research (Future Research Leader Programme), and the G€oran Gustafsson Foundation. J.Å. is a Royal Swedish Academy of Sciences Research Fellow supported by a grant from the Knut and Alice Wallenberg Foundation. V.B. acknowledges the G€oran Gustafsson Foundation and the Blanceflor Boncompagni-Ludovisi Foundation. P.V. acknowledges funding from the Basque Government through the ETORGAI Program, Project No. ER- 2010/00032 and Program No. PI2009-17, the Spanish Ministry of Science and Education under Projects No. CSD2006-53 and No. MAT2009-07980. J.N. acknowledges funding for the Generalitat de Catalunya and the Spanish Ministry of Science and Education through No. 2009-SGR-1292 and No. MAT2010-20616-C02 projects.Peer Reviewe