A Revised Validation Process for Ice Accretion Codes

A research project is underway at NASA Glenn to produce computer software that can accurately predict ice growth under any meteorological conditions for any aircraft surface. This report will present results from the latest LEWICE release, version 3.5. This program differs from previous releases in its ability to model mixed phase and ice crystal conditions such as those encountered inside an engine. It also has expanded capability to use structured grids and a new capability to use results from unstructured grid flow solvers. A quantitative comparison of the results against a database of ice shapes that have been generated in the NASA Glenn Icing Research Tunnel (IRT) has also been performed. This paper will extend the comparison of ice shapes between LEWICE 3.5 and experimental data from a previous paper. Comparisons of lift and drag are made between experimentally collected data from experimentally obtained ice shapes and simulated (CFD) data on simulated (LEWICE) ice shapes. Comparisons are also made between experimentally collected and simulated performance data on select experimental ice shapes to ensure the CFD solver, FUN3D, is valid within the flight regime. The results show that the predicted results are within the accuracy limits of the experimental data for the majority of cases

Determining the exit time distribution for a closed cyclic network

AbstractConsider a closed, N-node, cyclic network, where each node has an independent, exponential single server. Using lattice-Bessel functions, we can explicitly solve for the transition probabilities of events that occur prior to one of the nodes becoming empty. This calculation entails associating with this absorbing process a symmetry group that is the semidirect product of simpler groups. As a byproduct, we are able to compute explicitly the entire spectrum for the finite-dimensional matrix generator of this process. When the number of nodes exceeds 1, such a spectrum is no longer purely real. Moreover, we are also able to obtain the quasistationary distribution or the limiting behavior of the network conditioned on no node ever being idle

Interstate Voter Registration Database Matching: The Oregon-Washington 2008 Pilot Project

Voter registration databases maintain lists of registered voters that are used to determine who is and is not eligible to vote in an election. As such, accurate voter registration databases form a cornerstone of the electoral process. In the United States, each state maintains its own voter registration database. It is not uncommon for a voter to become registered in two states, for example as a result of moving from one state to the other or of living in one state and working in one another. In this paper, we report on a pilot interstate voter registration database matching project between the two states of Oregon andWashington whose goal was to explore the feasibility of using database matching to identify voters registered in the two states, and to do so with as much openness and transparency as possible. We describe the matching algorithms used, the procedures taken with found matches, and the resulting actions taken on actual voter registrations. We also discuss several directions for improving matching algorithms and procedures

Simulating Ice Accretion Effects on Engine Performance

Develop a modeling tool that can be used to predict the onset of engine icing due to ice crystal ingestion. The tool will be capable of modeling the effects of ice build up as well as its effect on engine performance. Perform a parametric study of an engine with simulated ice blockage effects at altitude conditions. Using the tool, estimate the effect of blockage in the low pressure compressor due to ice buildup (accretion), and its effects on engine performance

Theology, News and Notes - Vol. 23, No. 04

Theology News & Notes was a theological journal published by Fuller Theological Seminary from 1954 through 2014.https://digitalcommons.fuller.edu/tnn/1061/thumbnail.jp

Mixed Phase Modeling in GlennICE with Application to Engine Icing

A capability for modeling ice crystals and mixed phase icing has been added to GlennICE. Modifications have been made to the particle trajectory algorithm and energy balance to model this behavior. This capability has been added as part of a larger effort to model ice crystal ingestion in aircraft engines. Comparisons have been made to four mixed phase ice accretions performed in the Cox icing tunnel in order to calibrate an ice erosion model. A sample ice ingestion case was performed using the Energy Efficient Engine (E3) model in order to illustrate current capabilities. Engine performance characteristics were supplied using the Numerical Propulsion System Simulation (NPSS) model for this test case

Steel Pipe Pile Design, Installation, and Dynamic Testing for a New Pier in Georgetown, SC

A new pier extension was constructed for the South Carolina State Ports Authority (SCSPA) at Pier 31C in Georgetown, South Carolina. This pier was founded on 28 steel open ended pipe (OEP) piles driven into the underlying limestone and silts of the Pee Dee Formation. To account for the expected high lateral loads the new pier may experience during ship impacts and movements, both vertical and batter piles were installed. To the authors’ knowledge, this is the first application of steel open ended pipe piles as a maritime foundation system in the Georgetown, South Carolina area. The soil stratigraphy at the site consisted of soft river deposits overlaying interbedded limestone and silt layers of the Pee Dee Formation. Significant pile penetration into the cohesive deposits of the Pee Dee Formation was necessary to generate the required tension pile capacity. The results of the geotechnical investigation suggested that the intermittent limestone layers would cause difficult driving conditions for pre-stressed concrete piles, which are traditionally used in the area. This paper provides an overview of the project, discusses the selection and design processes and installation of the steel OEP piles, and presents the results of the dynamic load testing program conducted to verify the pile design. In addition, measurements of time dependent pile capacity gain and pile plugging made during pile installation are also presented and discussed