2,376 research outputs found
Data Analysis Techniques for Fan Performance in Highly-Distorted Flows from Boundary Layer Ingesting Inlets
The design of a unique distortion-tolerant fan for a high-bypass ratio boundary-layer ingesting propulsion system has been completed and a rig constructed and tested in the NASA Glenn 8x6 wind tunnel. Processing the data from the experiment presented some interesting challenges because of the complexity of the experimental setup and the flow through the test rig. The experiment was run in three phases, each of which employed a unique complement of inlet throat and fan face instrumentation to avoid the blockage that would have resulted from simultaneously installing all of the rakes. The measurement from the individual test points were subsequently combined to compute the overall stage performance. A CFD model of the experiment was used to gain understanding of the flow field and to test some of the techniques proposed for interpolating and extrapolating the measurements into regions where measurements were not made. This capability became extremely useful when it was discovered that there was an unexpected total temperature distortion in the tunnel. The CFD model was modified by inserting a total temperature profile at the upstream boundary that mimicked the measured distortion where measurements were available and that CFD solution was used to investigate methods to infer the complete total temperature field at the fan face
Searching for magnetic monopoles trapped in accelerator material at the Large Hadron Collider
If produced in high energy particle collisions at the LHC, magnetic monopoles
could stop in material surrounding the interaction points. Obsolete parts of
the beam pipe near the CMS interaction region, which were exposed to the
products of pp and heavy ion collisions, were analysed using a SQUID-based
magnetometer. The purpose of this work is to quantify the performance of the
magnetometer in the context of a monopole search using a small set of samples
of accelerator material ahead of the 2013 shutdown.Comment: 11 page
Indirect evaluation of Mars Gravity Model 2011 using a replication experiment on Earth
Curtin University’s Mars Gravity Model 2011 (MGM2011) is a high-resolution composite set of gravity field functionals that uses topography-implied gravity effects at medium- and short-scales (~125 km to ~3 km) to augment the space-collected MRO110B2 gravity model. Ground-truth gravity observations that could be used for direct validation of MGM2011 are not available on Mars’s surface. To indirectly evaluate MGM2011 and its modelling principles, an as-close-as-possible replication of the MGM2011 modelling approach was performed on Earth as the planetary body with most detailed gravity field knowledge available. Comparisons among six ground-truth data sets (gravity disturbances, quasigeoid undulations and vertical deflections) and the MGM2011-replication over Europe and North America show unanimously that topography-implied gravity information improves upon space-collected gravity models over areas with rugged terrain. The improvements are ~55% and ~67% for gravity disturbances, ~12% and ~47% for quasigeoid undulations, and ~30% to ~50% for vertical deflections. Given that the correlation between space-collected gravity and topography is higher for Mars than Earth at spatial scales of a few 100 km, topography-implied gravity effects are more dominant on Mars. It is therefore reasonable to infer that the MGM2011 modelling approach is suitable, offering an improvement over space-collected Martian gravity field models
Quantum protocols for anonymous voting and surveying
We describe quantum protocols for voting and surveying. A key feature of our
schemes is the use of entangled states to ensure that the votes are anonymous
and to allow the votes to be tallied. The entanglement is distributed over
separated sites; the physical inaccessibility of any one site is sufficient to
guarantee the anonymity of the votes. The security of these protocols with
respect to various kinds of attack is discussed. We also discuss classical
schemes and show that our quantum voting protocol represents a N-fold reduction
in computational complexity, where N is the number of voters.Comment: 8 pages. V2 includes the modifications made for the published versio
Development of a Flow Field for Testing a Boundary-Layer-Ingesting Propulsor
In order to test embedded-propulsor technology, modifications were required of the 8x6 Supersonic Wind tunnel at NASA Glenn Research Center. The extent of the modifications required that a new tunnel calibration be completed to generate a new calibration dataset and operational procedures for the tunnel, as well as to map the boundary layer on the raised floor. This report describes the propulsor inflow that was to be simulated, documents the tunnel modifications that were required, and conveys the results of the calibration test that was completed to measure the resulting flow properties
Development of a Rotating Rake Array for Boundary-Layer-Ingesting Fan-Stage Measurements
The recent Boundary-Layer-Ingesting Inlet/Distortion Tolerant Fan wind tunnel experiment at NASA Glenn Research Center's 8-foot by 6-foot supersonic wind tunnel examined the performance of a novel inlet and fan stage that was designed to ingest the vehicle boundary layer in order to take advantage of a predicted overall propulsive efficiency benefit. A key piece of the experiment's instrumentation was a pair of rotating rake arrays located upstream and downstream of the fan stage. This paper examines the development of these rake arrays. Pre-test numerical solutions were sampled to determine placement and spacing for rake pressure and temperature probes. The effects of probe spacing and survey density on the repeatability of survey measurements was examined. These data were then used to estimate measurement uncertainty for the adiabatic efficiency
Application of the penalty coupling method for the analysis of blood vessels
Due to the significant health and economic impact of blood vessel diseases on modern society, its analysis is becoming of increasing importance for the medical sciences. The complexity of the vascular system, its dynamics and material characteristics all make it an ideal candidate for analysis through fluid structure interaction (FSI) simulations. FSI is a relatively new approach in numerical analysis and enables the multi-physical analysis of problems, yielding a higher accuracy of results than could be possible when using a single physics code to analyse the same category of problems. This paper introduces the concepts behind the Arbitrary Lagrangian Eulerian (ALE) formulation using the penalty coupling method. It moves on to present a validation case and compares it to available simulation results from the literature using a different FSI method. Results were found to correspond well to the comparison case as well as basic theory
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