72 research outputs found
Reynolds Number Effects at High Angles of Attack
Lessons learned from comparisons between ground-based tests and flight measurements for the high-angle-of-attack programs on the F-18 High Alpha Research Vehicle (HARV), the X-29 forward-swept wing aircraft, and the X-31 enhanced fighter maneuverability aircraft are presented. On all three vehicles, Reynolds number effects were evident on the forebodies at high angles of attack. The correlation between flight and wind tunnel forebody pressure distributions for the F-18 HARV were improved by using twin longitudinal grit strips on the forebody of the wind-tunnel model. Pressure distributions obtained on the X-29 wind-tunnel model at flight Reynolds numbers showed excellent correlation with the flight data up to alpha = 50 deg. Above (alpha = 50 deg. the pressure distributions for both flight and wind tunnel became asymmetric and showed poorer agreement, possibly because of the different surface finish of the model and aircraft. The detrimental effect of a very sharp nose apex was demonstrated on the X-31 aircraft. Grit strips on the forebody of the X-31 reduced the randomness but increased the magnitude of the asymmetry. Nose strakes were required to reduce the forebody yawing moment asymmetries and the grit strips on the flight test noseboom improved the aircraft handling qualities
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Calculation of eddy-currents induced in a compact synchrotron superconducting magnet structure during a current ramp
Under DARPA sponsorship, a compact Superconducting X-Ray Light Source (SXSL) is being designed and built by the Brookhaven National Laboratory (BNL) with industry participation from Grumman Corporation and General Dynamics. The SXLS machine employs two 180{degrees} curved 4 telsa superconducting dipole magnets. These magnets are required to produce a dipole field for bending the beam but at the same time they must produce finite amounts of higher multipoles which are required for conditioning the beam. In fact uniformity of the field to less than 1 part in 10,000 must be maintained under all operating conditions. When a superconducting magnet is ramped from zero to full field, the changing magnetic field produces eddy-currents in the magnet structure which in turn can produce undesirable multipoles. This paper discusses a simple method for estimating these eddy-currents and their effect on the field harmonics. The paper present the analysis basis and its application to the SXLS magnet support structure and to the beam chamber components. 5 figs., 1 tab
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Performance of the Phase 1 superconducting x-ray lithography source (SXLS) at BNL
The Phase I SXLS electron storage ring has a circumference of 8.5 meters, it uses conventional dipole magnets, B {le} 1.1 T and p = 60 cm, and it is capable of operating in the range of 50--250 MeV. It is the forerunner of the Phase II SXLS ring which will operate at 700 MeV and will make use of superconducting dipoles, B{sub o} = 3.87 Tesla, as a source of {lambda}{sub c} = 10 angstrom x-rays for proximity printing lithography. The Phase I storage ring has been successfully commissioned; stored currents in excess of one ampere have been achieved. A report on the performance of the machine is presented
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