A Study of Ship Airwakes Using Dual Plane Stereoscopic PIV

The airwake of a model Simple Frigate Shape 2 (SFS2) was studied in a low-speed wind tunnel. This airwake was measured using a novel time-dependent, dual plane, stereoscopic particle image velocimetry approach. Two flow planes over the flight deck, one parallel and one perpendicular to the free-stream were simultaneously measured. Measurements were carried out over four such pairs of streamwise-spanwise plane combinations. Additionally, the airwake with and without a simulated atmospheric boundary layer (sABL) was studied. The synchronicity of the measurements were taken advantage of to carry out conditional averages of the flow field to isolate and study certain flow events (and its footprint) within the airwake. Those flow events that are likely relevant to rotorcraft operations in the vicinity of ships were chosen to carry out this conditional analysis. Conditionally averaged statistics of the large vertical fluctuations in the shear layer over the flight deck revealed sharp velocity gradients as well as large-scale flow features above and over large portions of the deck. The fields conditioned on large positive vertical fluctuations were opposite in sign (or the mirror) of those with large negative vertical fluctuations, pointing to a temporal symmetry associated with the oscillation of the shear layer. The flow scenario with the sABL showed similar turbulence levels with almost identical flow structures. An examination of the two stable flow states of the hangar door wake, based on conditional statistics, revealed that each state influenced nearly the entire flow field. Additionally, the mean temporal and spatial evolution of the airwake as the flow transitions between these two states was established. In the case of the flow with the sABL, both flow states persisted for shorter time periods. Overall this study strengthened the growing body of evidence that points to the airwake being a flow field that is a coupled or encapsulating flow structures that are interacting

Project Themyscira

Currently, both governments and private corporations are developing lunar exploration projects for scientific research and spaceflight operations. However, a viable plan for a lunar base is yet to be developed. The goal of Project Themyscira is to design a self-sufficient, sustainable lunar base capable of supporting five crew members for a period of six months. The feasibility study is two-fold. It will test the effectiveness and efficiency of the life-support systems to accomplish the mission, as well as evaluate its financial and logistic feasibility. In order to study the required systems to support human life, the team conducted an extensive literature survey on previous designs for human settlements in space and their limitations. This assessment yielded a series of constraints for oxygen production, atmospheric modeling, energy production, water treatment, and thermal regulation. Preliminary findings show that while some of the necessary support systems have the technology required to provide the necessary outputs, the logistics to set up the lunar base are not financially feasible. Nonetheless, artificial atmosphere models, artificial photosynthesis and radiation-protected photovoltaic cells are some of the existing technologies that would allow the lunar base to sustain human life. Consequently, optimizing the technologies so that they can be taken to space in smaller dimensions could result in logistical feasibility. The team will focus on developing testing methods to optimize the systems necessary to sustain the lunar base

Production of He-4 and (4) in Pb-Pb collisions at root(NN)-N-S=2.76 TeV at the LHC

Results on the production of He-4 and (4) nuclei in Pb-Pb collisions at root(NN)-N-S = 2.76 TeV in the rapidity range vertical bar y vertical bar <1, using the ALICE detector, are presented in this paper. The rapidity densities corresponding to 0-10% central events are found to be dN/dy4(He) = (0.8 +/- 0.4 (stat) +/- 0.3 (syst)) x 10(-6) and dN/dy4 = (1.1 +/- 0.4 (stat) +/- 0.2 (syst)) x 10(-6), respectively. This is in agreement with the statistical thermal model expectation assuming the same chemical freeze-out temperature (T-chem = 156 MeV) as for light hadrons. The measured ratio of (4)/He-4 is 1.4 +/- 0.8 (stat) +/- 0.5 (syst). (C) 2018 Published by Elsevier B.V.Peer reviewe

Vertical Lift Research Center of Excellence (VLRCOE)

Ship airwakes are the unsteady turbulent flows that are generated by the earths atmospheric boundary layer (the wind colloquially) blowing over a ship. These flow fields are highly turbulent, not easy to predict and couple with a similar wake flow field generated by a rotorcraft operating close the the ship. This coupling as expected is extremely difficult to predict let along faithfully simulate in a flight simulator. This coupling can have catastrophic consequences for the operation or rotorcraft operating in the vicinity of Naval ships. While ship airwakes have now been studied for several decades, there remain many unanswered questions and associated challenges in understanding these unsteady, three-dimensional flows, particularly concerning their turbulence characteristics and how flow scales in the airwake can potentially couple with those of a rotorcraft, including Unoccupied Aerial Systems (UAS). Navy personnel and aircraft safety remain the primary motivating factor for understanding the airwake and the interactions so produced. In this regard, developing a versatile, high-fidelity mathematical model to represent the ship airwake in a flight simulation, such as using a reduced-order mathematical representation, remains a priority for the technical community. This goal is particularly critical for more contemporary ship shapes typical of the current Navy inventory. It is toward this end that the fluid dynamic studies of the airwake are addressed in this proposed task. Furthermore, a vast majority of ship airwake measurements have not considered the interactions between an operating rotor(craft) and the airwake, another challenge the proposed task will address. Overall, the mean flow features of the ship airwake are currently reasonably well characterized, at least for simplified ship superstructures such as the SFS2. However, much of the combined spatio-temporal behavior of the ship airwake, in general, has not been measured and so the physics are still poorly understood, particularly for contemporary Navy ship shapes. Organized turbulence structures, their distribution of energy across different scales, and their interactions with, or influence on, or criticality for, a traditional rotorcraft or less conventional UAS are not understood or sufficiently documented so far. The recent time-resolved airwake measurements of the current PIs have better established the true three-dimensional nature of the ship airwake, along with other turbulent aspects of the flow that have not been previously documented. These features include the high degree of intermittency, the bistable nature of the airwake, etc. These recent measurements have highlighted the predominance of low frequencies in the airwake, but not exclusively so. They indicate the likelihood of coupling with the response of any rotor system, large or small These new measurements have emphasized the need for spatially and temporally resolved high-frequency flow measurements that capture the true three-dimensionality of the airwake flow and its turbulent aspects, including intermittency. In addition, parsing these measurements into low-order mathematical models (such as for use in FlightLab or similar) remains a challenge, both in the context of understanding the flow physics and developing a higher-fidelity representation of the airwake for use in piloted simulations. Furthermore, the challenge of measuring, understanding, and representing the interactions between the airwake and a rotor system still remains to be studied at the fidelity needed if faithful models of the airwake are to be realized. Technical Objectives (ERAU tasks only): 1) With the focus on faithfully capturing the three-dimensionality of the flow and its turbulent aspects (such as the frequency content and intermittency), time-resolved particle image velocimetry (TR-PIV) measurements with high spatio-temporal resolution will be conducted. These measurements are proposed for a more relevant ship geometry, namely the NATO Generic Destroyer (GD) of NATO AVT-315, while also investigating the differences to the widely used SFS2. Also, a representative rotor system will be introduced into the airwake to study the interactions therein. ERAU will use their new subsonic 4x6 ft wind tunnel with a mostly glass test section and the large field of view TR-PIV system awarded under an ONR DURIP. The focus will be on carrying out dual-plane, time-resolved stereo PIV (DPTR-sPIV) measurements, which allow for spatially and temporally synchronous measurements. 2) These datasets will then be used to represent the flow field using reduced-order models (ROMs). The advantages of methods such as wavelets, spectral POD (sPOD), Multi-scale Proper Orthogonal Decomposition (mPOD), and probabilistic/statistics techniques, will be used to acquire physical insights into the complex airwake environment, while describing the flow in a manner that is more relevant to the scales of UAS. This proposed approach will also offer new quantitative metrics for comparing airwakes, sorted into frequencies, which quantitatively reflect the energy distributions, and so they are much more suitable for V&V. ROMs can then be constructed, and flow field physics and interactions can be examined at each scale, whose contours should be comparable across all frequencies

Informe final del proyecto: Bases para la adaptación agronómica del Tinopiro (Intermediate wheatgrass, Thinopyrum intermedium) en regiones templadas

Los cultivos anuales predominan ampliamente la tierra arable del planeta siendo la principal fuente de recursos para la alimentación humana. Sin embargo, su uso en la agricultura está asociado a erosión de suelo y contaminación de aguas. Tinopiro (Thinopyrun intermedium) es actualmente la especie con mayores posibilidades de consolidarse como un cultivo doble propósito de grano perenne para consumo humano en el mundo. Sin embargo, el mejoramiento genético se ha realizado en regiones frías de norte América. El objetivo general de este proyecto fue evaluar agronómicamente familias de Tinopiro, conocer las posibilidades de mejoramiento genético dado el germoplasma estudiado y seleccionar germoplasma con adaptación agronómica básica a las condiciones templadas como las de Uruguay. Como objetivo específico, además nos propusimos conocer aquellos factores socio-económicos y percepciones de actores relevantes que favorecerían la adopción del cultivo. Treinta familias fueron evaluadas a campo por características de interés agronómico en la Estación experimental Mario A. Cassinoni, Paysandú, durante dos años consecutivos. La varianza genética asociada a estos caracteres fue importante tanto entre como dentro de las familias. Por su parte, la heredabilidad en sentido estricto fue de media a alta para la mayoría de los caracteres evaluados, indicando que la selección fenotípica convencional por estos caracteres sería factible otorgando importantes ganancias genéticas por cada ciclo de selección. La correlación genética entre varios componentes de rendimiento en grano y producción de forraje fue alta, indicando la posibilidad de seleccionar por rendimiento en grano y al mismo tiempo mejorar la producción de forraje bajo nuestras condiciones. A partir de la evaluación de planta individual (1000 plantas) durante dos años, utilizando un índice de selección estandarizado por precocidad y espigas por planta, se lograron seleccionar las mejores 6 plantas, cuya progenie se ha multiplicado y compone el núcleo de semilla con adaptación básica al que nos propusimos llegar con este proyecto. Tanto productores, técnicos como investigadores coinciden en que las mayores ventajas de un cultivo como Tinopiro radican en su condición de cultivo doble propósito, aumentando la diversificación el sistema productivo, permitiendo obtener ingresos adicionales. Por otro lado, el bajo costo de implantación, productividad de forraje y grano y capacidad de producción en suelos restrictivos son los factores principales destacados por estos actores, que favorecerían la adopción de Tinopiro en Uruguay. Los resultados de este proyecto son auspiciosos, aunque mucho queda por hacer para consolidar un cultivo con características agro-ambientales únicas como Tinopiro en nuestros sistemas de producción.Agencia Nacional de Investigación e Innovació

Informe final del proyecto: Bases para la adaptación agronómica del Tinopiro (Intermediate wheatgrass, Thinopyrum intermedium) en regiones templadas

Los cultivos anuales predominan ampliamente la tierra arable del planeta siendo la principal fuente de recursos para la alimentación humana. Sin embargo, su uso en la agricultura está asociado a erosión de suelo y contaminación de aguas. Tinopiro (Thinopyrun intermedium) es actualmente la especie con mayores posibilidades de consolidarse como un cultivo doble propósito de grano perenne para consumo humano en el mundo. Sin embargo, el mejoramiento genético se ha realizado en regiones frías de norte América. El objetivo general de este proyecto fue evaluar agronómicamente familias de Tinopiro, conocer las posibilidades de mejoramiento genético dado el germoplasma estudiado y seleccionar germoplasma con adaptación agronómica básica a las condiciones templadas como las de Uruguay. Como objetivo específico, además nos propusimos conocer aquellos factores socio-económicos y percepciones de actores relevantes que favorecerían la adopción del cultivo. Treinta familias fueron evaluadas a campo por características de interés agronómico en la Estación experimental Mario A. Cassinoni, Paysandú, durante dos años consecutivos. La varianza genética asociada a estos caracteres fue importante tanto entre como dentro de las familias. Por su parte, la heredabilidad en sentido estricto fue de media a alta para la mayoría de los caracteres evaluados, indicando que la selección fenotípica convencional por estos caracteres sería factible otorgando importantes ganancias genéticas por cada ciclo de selección. La correlación genética entre varios componentes de rendimiento en grano y producción de forraje fue alta, indicando la posibilidad de seleccionar por rendimiento en grano y al mismo tiempo mejorar la producción de forraje bajo nuestras condiciones. A partir de la evaluación de planta individual (1000 plantas) durante dos años, utilizando un índice de selección estandarizado por precocidad y espigas por planta, se lograron seleccionar las mejores 6 plantas, cuya progenie se ha multiplicado y compone el núcleo de semilla con adaptación básica al que nos propusimos llegar con este proyecto. Tanto productores, técnicos como investigadores coinciden en que las mayores ventajas de un cultivo como Tinopiro radican en su condición de cultivo doble propósito, aumentando la diversificación el sistema productivo, permitiendo obtener ingresos adicionales. Por otro lado, el bajo costo de implantación, productividad de forraje y grano y capacidad de producción en suelos restrictivos son los factores principales destacados por estos actores, que favorecerían la adopción de Tinopiro en Uruguay. Los resultados de este proyecto son auspiciosos, aunque mucho queda por hacer para consolidar un cultivo con características agro-ambientales únicas como Tinopiro en nuestros sistemas de producción.Agencia Nacional de Investigación e Innovació

Multiplicity dependence of light (anti-)nuclei production in p–Pb collisions at sNN=5.02 TeV

The measurement of the deuteron and anti-deuteron production in the rapidity range −1 < y < 0 as a function of transverse momentum and event multiplicity in p–Pb collisions at √sNN = 5.02 TeV is presented. (Anti-)deuterons are identified via their specific energy loss dE/dx and via their time-of- flight. Their production in p–Pb collisions is compared to pp and Pb–Pb collisions and is discussed within the context of thermal and coalescence models. The ratio of integrated yields of deuterons to protons (d/p) shows a significant increase as a function of the charged-particle multiplicity of the event starting from values similar to those observed in pp collisions at low multiplicities and approaching those observed in Pb–Pb collisions at high multiplicities. The mean transverse particle momenta are extracted from the deuteron spectra and the values are similar to those obtained for p and particles. Thus, deuteron spectra do not follow mass ordering. This behaviour is in contrast to the trend observed for non-composite particles in p–Pb collisions. In addition, the production of the rare 3He and 3He nuclei has been studied. The spectrum corresponding to all non-single diffractive p-Pb collisions is obtained in the rapidity window −1 < y < 0 and the pT-integrated yield dN/dy is extracted. It is found that the yields of protons, deuterons, and 3He, normalised by the spin degeneracy factor, follow an exponential decrease with mass number

Pseudorapidity densities of charged particles with transverse momentum thresholds in pp collisions at √ s = 5.02 and 13 TeV

The pseudorapidity density of charged particles with minimum transverse momentum (pT) thresholds of 0.15, 0.5, 1, and 2 GeV/c is measured in pp collisions at the center of mass energies of √s=5.02 and 13 TeV with the ALICE detector. The study is carried out for inelastic collisions with at least one primary charged particle having a pseudorapidity (η) within 0.8pT larger than the corresponding threshold. In addition, measurements without pT-thresholds are performed for inelastic and nonsingle-diffractive events as well as for inelastic events with at least one charged particle having |η|2GeV/c), highlighting the importance of such measurements for tuning event generators. The new measurements agree within uncertainties with results from the ATLAS and CMS experiments obtained at √s=13TeV.