Performance and Stability Characteristics of an Electrodynamically Levitated Vehicle Over a Split Guideway

1976 ◽  
Vol 98 (3) ◽  
pp. 277-285 ◽  
Author(s):  
J. Y. Wong ◽  
J. P. Howell ◽  
R. G. Rhodes ◽  
B. E. Mulhall

The results of an investigation into the performance and stability characteristics of an electrodynamically levitated vehicle using an integrated magnet system over a flat split guideway are described. The effects of system parameters on the lift/drag ratio, guidance and directional stability are examined in detail.

Author(s):  
Yang Zhang ◽  
Zhou Zhou ◽  
Kelei Wang ◽  
Zhongyun Fan

Focusing on the aerodynamic characteristics of the blended wing body (BWB) aircraft with boundary layer ingestion(BLI) distributed propulsion system; the influences of propulsion system parameters under the condition of cruise and takeoff are studied. Firstly, based on the momentum source method (MSM), the NASA ducted propeller model is simulated, which verifies the reliability of the numerical method in this paper. Then, by using the method of structural grid and S-A turbulence model to solve the Reynolds averaged Navier-Stokes (RANS) equation, the aerodynamic characteristics of the BLI UAV model with D80 ducted fan in cruise state are numerically calculated. It is proved that the advantage of the BLI distributed propulsion system is superior in increasing lift. And the aerodynamic characteristics of the BLI UAV with different propulsion system parameters are compared. At last, the aerodynamic effect of ducted fan thrust on the BLI UAV is carried out. The results show that, due to the suction function of the BLI distributed propulsion system, the air flow velocity near the BWB fuselage is effectively accelerated, and the flow along the spanwise is restrained, which improves the lift coefficient about 16% and lift-to-drag ratio about 10%. Under the condition of equal thrust, the D80 ducted fan brings larger load of the propeller, which makes the static pressure at the inlet and outlet smaller. Compared with D150 ducted fan, the lift-to-drag ratio is increased by 15%. When aircraft takes off, increasing the thrust of the ducted fan can reduce the possibility of flow separation on the upper surface of the fuselage, which is conducive to the safety.


1979 ◽  
Vol 46 ◽  
pp. 65-74 ◽  
Author(s):  
A.C. Fabian ◽  
J.E. Pringle ◽  
J.A.J. Whelan ◽  
J.A. Bailey

Abstract.Recent photometric and spectroscopic observations of the dwarf nova system Z Cha are discussed. Methods for constraining the system parameters are applied and the disc emissivity is deduced as a function of radius. Indications are found that the disc shrinks in size with increasing time after outburst.


1984 ◽  
Vol 45 (C1) ◽  
pp. C1-233-C1-239 ◽  
Author(s):  
L. Resegotti
Keyword(s):  

2002 ◽  
Vol 90 ◽  
pp. 65-66 ◽  
Author(s):  
Kazuya Oguri ◽  
Akihiro Mizutani ◽  
Sanshiro Ogino ◽  
Yasuzumi Ochial ◽  
Yoshitake Nishi
Keyword(s):  

1977 ◽  
Vol 37 (02) ◽  
pp. 243-252
Author(s):  
Yi-Hsiang Chen ◽  
E. B Reeve

SummaryTo shed some light on the homeostatic regulation of plasma fibrinogen, metabolic studies were made in healthy females, and in normal, thyroidectomized, and thyroxine-treated rabbits. In females, compared with normal males, plasma fibrinogen concentration, plasma and interstitial fibrinogen decreased consequent to an increased fractional catabolic rate and a normal fibrinogen synthesis rate. The interstitial/plasma fibrinogen ratio remained unchanged. In normal rabbits, with increasing body weight fractional catabolic rate and catabolic rate decreased, while fibrinogen concentration and plasma fibrinogen remained constant owing to a simultaneous decrease in fibrinogen synthesis. In addition, fractional transcapillary transfer rate and transcapillary flux also decreased resulting in a shrinkage of interstitial fibrinogen. Thyroidectomy and thyroxine-injection markedly altered fibrinogen metabolism: thyroid hormone accelerated fibrinogen catabolism but also stimulated synthesis. The net result was an increase in plasma fibrinogen and fibrinogen concentration. The interstitial/plasma fibrinogen ratio decreased in thyroxine-treated, and increased in thyroidectomized animals. This study defines the variations of the fibrinogen system parameters in these physiologic and pathologic conditions, and illustrates some patterns of alterations in fibrinogen metabolism.


2020 ◽  
Vol 64 (1-4) ◽  
pp. 1495-1504
Author(s):  
Fangchao Xu ◽  
Yongquan Guo ◽  
Ran Zhou ◽  
Junjie Jin ◽  
Chuan Zhao ◽  
...  

To solve the problem of reduction of suspension force of permanent magnet system with variable magnetic flux path control, according to the structure of the system, suspension principle of the permanent magnet system with variable magnetic flux path control and the generation principle of the load torque, the influence of the mechanical structure of the system on the suspension force is analyzed by changing part of parameters of the system structure. The results show that the existence of magnetic isolation plate is the main reason for the decrease of suspension force, the permanent magnet ring can be thickened to 11.91 mm, the annular gap can be reduced to 1 mm, thickness of the “F” shaped magnetizer can be increased to 9 mm to increase the suspension force.


Sign in / Sign up

Export Citation Format

Share Document