Basic research in wake vortex alleviation using a variable twist wing

The variable twist wing concept was used to investigate the relative effects of lift and turbulence distribution on the rolled up vortex wake. Several methods of reducing the vortex strength behind an aircraft were identified. These involve the redistribution of lift spanwise on the wing and drag distribution along the wing. Initial attempts to use the variable twist wing velocity data to validate the WAKE computer code have shown a strong correlation, although the vorticity levels were not exactly matched

Detailed pressure distribution measurements obtained on several configurations of an aspect-ratio-7 variable twist wing

Detailed pressure distribution measurements were made for 11 twist configurations of a unique, multisegmented wing model having an aspect ratio of 7 and a taper ratio of 1. These configurations encompassed span loads ranging from that of an untwisted wing to simple flapped wings both with and without upper-surface spoilers attached. For each of the wing twist configurations, electronic scanning pressure transducers were used to obtain 580 surface pressure measurements over the wing in about 0.1 sec. Integrated pressure distribution measurements compared favorably with force-balance measurements of lift on the model when the model centerbody lift was included. Complete plots and tabulations of the pressure distribution data for each wing twist configuration are provided

Low-speed wind-tunnel investigation of wing fins as trailing-vortex-alleviation devices on a transport airplane model

The trailing-vortex-alleviation effectiveness of both a one- and a two-fin configuration (semicircular with a radius of 0.043 semispan) on a jumbo-jet transport airplane model in its landing configuration was investigated in the Langley V/STOL tunnel, by the trailing-wing sensor technique. The fins were located on the upper surface of the transport model wing along the 30-percent-chord line. The fin configurations were effective in reducing the vortex-induced rolling moment, by amounts varying from 28 to 60 percent, on the trailing wing model located at a distance of 7.8 transport model wing spans downstream of the transport model. The flow over the fins and over the transport airplane model wing downstream of the fins was observed to be separated and turbulent. All fin configurations caused a reduction in maximum lift coefficient, a positive increment in drag coefficient, and an increment in nose-up pitching-moment coefficient on the transport airplane model

Neither deathsquads nor democrats : explaining the behavior of the Salvadoran military.

Thesis (M.A.

Understanding the British Columbia Hydrogen and Fuel Cells Cluster: A Case Study of Public Laboratories and Private Research

This study looks at the cluster using a structured approach that tests clusters against indicators of current conditions and current performance. It includes the results of an extensive interview program and survey of professionals in the field, both within the cluster and elsewhere. The results give a clear picture of a cluster that has two major components – hydrogen based industries and fuel cell technologies, which are both global in reach and potential

The Innovation System Research Network (ISRN): A Canadian Experiment in Knowledge Management

This paper looks at the creation and function of the Innovation Systems Research Network (ISRN), which is a collaborative Canadian initiative to undertake and disseminate research results concerning the diverse nature of regional and local innovation systems across the country

Living in a Battleground: Presidential Campaigns and Fundamental Predictors of Vote Choice

Little evidence links the strategic decisions of campaigns to individual-level voting behavior. Yet for campaigns to matter in the way that experts argue, exposure to campaigns must also matter so there should be observable differences in the structure of vote choice between battleground and non-battleground states. Combining presidential campaign data with the Senate Election Study, we show that intense campaigning can activate factors like race, ideology, partisanship, and presidential approval. We find that the campaigns affected different variables in 1988 than in 1992, which we hypothesize is the consequence of campaign messages