LES of an Inclined Jet into a Supersonic Turbulent Crossflow

This short article describes flow parameters, numerical method, and animations of the fluid dynamics video "LES of an Inclined Jet into a Supersonic Turbulent Crossflow" (http://ecommons.library.cornell.edu/bitstream/1813/14073/3/GFM-2009.mpg [high-resolution] and http://ecommons.library.cornell.edu/bitstream/1813/14073/2/GFM-2009-web.m1v [low-resolution] video). We performed large-eddy simulation with the sub-grid scale (LES-SGS) stretched-vortex model of momentum and scalar transport to study the gas-dynamics interactions of a helium inclined round jet into a supersonic ($M=3.6$) turbulent (\Reth$=13\times10^3$) air flow over a flat surface. The video shows the temporal development of Mach-number and magnitude of density-gradient in the mid-span plane, and isosurface of helium mass-fraction and \lam_2 (vortical structures). The identified vortical structures are sheets, tilted tubes, and discontinuous rings. The vortical structures are shown to be well correlated in space and time with helium mass-fraction isosurface ($Y_{\rm He}=0.25$).Comment: 7 pages, 1 figure, 1 table, article describing fluid dynamics video submitted to Gallery of Fluid Motion, APS-DFD 200

Unemployment compensation: An Automatic Stabilizer

Thesis (M.B.A)--Boston Universit

Business Failure and the Lottery Syndrome: A Note

A significant number of new business failures can be traced to the fact that the founder(s) missed the mark on many of these traits required for success. They may not have inspired confidence in anyone, including themselves. They may have been easily upset by problems. They may have had difficulty in maintaining any internal optimism with no clear vision or realistic goals. Lastly, they may have succumbed to wishful thinking and the need for instant gratification with the material trappings of the business; thus creating an emotional foundation for failure

Evaluation of a stall-flutter spring-damper pushrod in the rotating control system of a CH-54B helicopter

Results of a design and flight test program conducted to define the effect of rotating pushrod damping on stall-flutter induced control loads are presented. The CH-54B helicopter was chosen as the test aircraft because it exhibited stall induced control loads. Damping was introduced into the CH-54B control system by replacing the standard pushrod with spring-damper assemblies. Design features of the spring-damper are described and the results of a dynamic analysis are shown which define the pushrod stiffness and damping requirements. Flight test measurements taken at 47,000 lb gross weight with and without the damper are presented. The results indicate that the spring-damper pushrods reduced high frequency, stall-induced rotating control loads by almost 50%. Fixed system control loads were reduced by 40%. Handling qualities in stall were unchanged, as expected

Residential fire detection

"Residential fires have become a significant problem throughout the U.S. The National Fire Protection Association (NFPA) estimates that in 1982 residential fires in the U.S. killed 4,940 persons and resulted in injury to 21,100 more. In addition, these residential fires accounted for an estimated $3,253,000,000 in property damage. Figure 1 shows the causes of residential fires as reported by the Federal Emergency Management Agency in its National Fire Incident Reporting System. The leading causes of fires in one-and-two family dwellings were heating (31 percent), cooking (15 percent), and incendiary or suspicious (10 percent). In residential properties, cigarettes are still the leading cause of accidental multiple death fires (those fires that are fatal to three or more persons) by a factor of two to one. Fires resulting from fixed or portable heating equipment-woodstoves, kerosene heaters, gas or electric cooking stoves, etc.,-are the second most common cause of accidental multipledeath fires in residential properties."--First page.David E. Baker (Department of Agricultural Engineering, College of Agriculture) and Paul Adams (Director, Missouri Fire and Rescue Training Institute, University of Missouri--Columbia)Revised 8/84/10

First Science Results From SOFIA/FORCAST: Super-Resolution Imaging of the S140 Cluster at 37\micron

We present 37\micron\ imaging of the S140 complex of infrared sources centered on IRS1 made with the FORCAST camera on SOFIA. These observations are the longest wavelength imaging to resolve clearly the three main sources seen at shorter wavelengths, IRS 1, 2 and 3, and are nearly at the diffraction limit of the 2.5-m telescope. We also obtained a small number of images at 11 and 31\micron\ that are useful for flux measurement. Our images cover the area of several strong sub-mm sources seen in the area -- SMM 1, 2, and 3 -- that are not coincident with any mid-infrared sources and are not visible in our longer wavelength imaging either. Our new observations confirm previous estimates of the relative dust optical depth and source luminosity for the components in this likely cluster of early B stars. We also investigate the use of super-resolution to go beyond the basic diffraction limit in imaging on SOFIA and find that the van Cittert algorithm, together with the "multi-resolution" technique, provides excellent results