7 Matching Results

Search Results

Advanced search parameters have been applied.

Characteristics of Low-Aspect-Ratio Wings at Supercritical Mach Numbers

Description: "The separation of the flow over wings precipitated by the compression shock that forms as speeds are increased into the supercritical Mach number range has imposed serious difficulties in the improvement of aircraft performance. Three difficulties rise principally as a consequence of the rapid drag rise and the loss of lift that causes serious stability changes when the wing shock-stalls. Favorable relieving effects due to the three-dimensional flow around the tips were obtained and these effects were of such magnitude that it is indicated that low-aspect-ratio wings offer a possible solution of the problems encountered" (p. 1).
Date: 1949
Creator: Stack, John & Lindsey, W. F.
Partner: UNT Libraries Government Documents Department

Lift, Drag, and Pitching Moment of Low-Aspect-Ratio Wings at Subsonic and Supersonic Speeds : Plane Tapered Wing of Aspect Ratio 3.1 with 3-Percent-Thick, Biconvex Section

Description: "A wing-body combination having a plane tapered wing of aspect ratio 3.1 and 3-percent-thick, biconvex sections in streamwise planes has been investigated at both subsonic and supersonic Mach numbers. The lift, drag, and pitching moment of the model are presented for Mach numbers from 0.60 to 0.925 and 1.20 to 1.90 at a Reynolds number of 2.4 million. Results are also presented for Mach numbers from 0.60 to 0.925 and 1.20 to 1.50 at Reynolds numbers of 1.5 million and 3.8 million" (p. 1).
Date: January 30, 1951
Creator: Reese, David E. & Phelps, E. Ray
Partner: UNT Libraries Government Documents Department

Stability and control characteristics of a free-flying model with an unswept wing of aspect ratio 3 (XS-3)

Description: The results of power-off force tests and flight tests of a model with a thin unswept low-aspect-ratio wing are presented. The tests were made with the flaps retracted and deflected. The effects on the lateral flight characteristics of decreasing directional stability were noted.
Date: November 15, 1948
Creator: Bennett, Charles V. & Hassell, James L., Jr.
Partner: UNT Libraries Government Documents Department

Characteristics of Low-Aspect Ratio Wings at Supercritical Mach Numbers

Description: Note presenting experiments to study the characteristics of low-aspect-ratio wings at supercritical Mach numbers. The experiments consisted of tests of wings of aspect ratios ranging from infinity to 2. The results indicate that the detrimental effects of compressibility in the supercritical speed range on the stability and performance of aircraft are alleviated to a great degree by the use of low-aspect-ratio lifting surfaces.
Date: August 1948
Creator: Stack, John & Lindsey, W. F.
Partner: UNT Libraries Government Documents Department

Reactor Configuration Development for ARIES-CS

Description: New compact, quasi-axially symmetric stellarator configurations have been developed as part of the ARIES-CS reactor studies. These new configurations have good plasma confinement and transport properties, including low losses of α particles and good integrity of flux surfaces at high β. We summarize the recent progress by showcasing two attractive classes of configurations — configurations with judiciously chosen rotational transforms to avoid undesirable effects of low order resonances on the flux surface integrity and configurations with very small aspect ratios (∼2.5) that have excellent quasi-axisymmetry and low field ripples.
Date: September 27, 2005
Creator: Ku LP, the ARIES-CS Team
Partner: UNT Libraries Government Documents Department

Modular Coil Design for the Ultra-low Aspect Ratio Quasi-axially Symmetric Stellarator MHH2

Description: A family of two field-period quasi-axisymmetric stellarators generally known as MHH2 with aspect ratios of only {approx}2.5 was found. These configurations have low field ripples and excellent confinement of {alpha} particles. This discovery raises the hope that a compact stellarator reactor may eventually be designed with the property of tokamak transport and stellarator stability. In this paper we demonstrate that smooth modular coils may be designed for this family of configurations that not only yield plasmas with good physics properties but also possess engineering properties desirable for compact power producing reactors. We show designs featuring 16 modular coils with ratios of major radius to minimum coil-plasma separation {approx}5.5, major radius to minimum coil-coil separation {approx}10 and the maximum field in coil bodies to the field on axis {approx}2 for 0.2 m{sup 2} conductors. These coils is expected to allow plasmas operated at 5% {beta} with {alpha} energy loss < 10% for a reactor of major radius <9 m at 5 T.
Date: September 27, 2005
Creator: Ku LP, the ARIES-CS Team
Partner: UNT Libraries Government Documents Department

Experiments with Liquid Metal Walls: Status of the Lithium Tokamak Experiment

Description: Liquid metal walls have been proposed to address the first wall challenge for fusion reactors. The Lithium Tokamak Experiment (LTX) at the Princeton Plasma Physics Laboratory (PPPL) is the first magnetic confinement device to have liquid metal plasma-facing components (PFC's) that encloses virtually the entire plasma. In the Current Drive Experiment-Upgrade (CDX-U), a predecessor to LTX at PPPL, the highest improvement in energy confinement ever observed in Ohmically-heated tokamak plasmas was achieved with a toroidal liquid lithium limiter. The LTX extends this liquid lithium PFC by using a conducting conformal shell that almost completely surrounds the plasma. By heating the shell, a lithium coating on the plasma-facing side can be kept liquefied. A consequence of the low-recycling conditions from liquid lithium walls is the need for efficient plasma fueling. For this purpose, a molecular cluster injector is being developed. Future plans include the installation of a neutral beam for core plasma fueling, and also ion temperature measurements using charge-exchange recombination spectroscopy. Low edge recycling is also predicted to reduce temperature gradients that drive drift wave turbulence. Gyrokinetic simulations are in progress to calculate fluctuation levels and transport for LTX plasmas, and new fluctuation diagnostics are under development to test these predictions. __________________________________________________
Date: February 16, 2010
Creator: Kaita, Robert; Boyle, Dennis; Gray, Timothy; Granstedt, Erik; Hammett, Gregory; Jacobson, Craig M et al.
Partner: UNT Libraries Government Documents Department