6,499 research outputs found
Evaluation of a Wake Vortex Upset Model Based on Simultaneous Measurements of Wake Velocities and Probe-Aircraft Accelerations
Simultaneous measurements were made of the upset responses experienced and the wake velocities encountered by an instrumented Learjet probe aircraft behind a Boeing 747 vortex-generating aircraft. The vortex-induced angular accelerations experienced could be predicted within 30% by a mathematical upset response model when the characteristics of the wake were well represented by the vortex model. The vortex model used in the present study adequately represented the wake flow field when the vortices dissipated symmetrically and only one vortex pair existed in the wake
A flight investigation of the wake turbulence alleviation resulting from a flap configuration change on a B-747 aircraft
A flight test investigation was conducted to evaluate the effects of a flap configuration change on the vortex wake characteristics of a Boeing 747 (B-747) aircraft as measured by differences in upset response resulting from deliberate vortex encounters by a following Learjet aircraft and by direct measurement of the velocities in the wake. The flaps of the B-747 have a predominant effect on the wake. The normal landing flap configuration produces a strong vortex that is attenuated when the outboard flap segments are raised; however, extension of the landing gear at that point increases the vortex induced upsets. These effects are in general agreement with existing wind tunnel and flight data for the modified flap configuration
Some measurements of the dynamic and static stability of two blunt-nosed, low-fineness- ratio bodies of revolution in free flight at mequal4
Dynamic and static stability of two blunt nosed low fineness ratio bodies of revolution in free flight - ballistic
Dynamic flight behavior of a ballasted sphere at Mach numbers from 0.4 to 14.5
Dynamic flight characteristics of ballasted sphere at various speed
FREE-FLIGHT MEASUREMENTS OF STATIC AND DYNAMIC STABILITY OF MODELS OF THE PROJECT MERCURY RE-ENTRY CAPSULE AT MACH NUMBERS 3 AND 9.5
Static & dynamic stability of mercury reentry capsule scale models at mach 3 & 9.
SAtlas: Spherical Versions of the Atlas Stellar Atmosphere Program
Context: The current stellar atmosphere programs still cannot match some
fundamental observations of the brightest stars, and with new techniques, such
as optical interferometry, providing new data for these stars, additional
development of stellar atmosphere codes is required. Aims: To modify the
open-source model atmosphere program Atlas to treat spherical geometry,
creating a test-bed stellar atmosphere code for stars with extended
atmospheres. Methods: The plane-parallel Atlas has been changed by introducing
the necessary spherical modifications in the pressure structure, in the
radiative transfer and in the temperature correction. Results: Several test
models show that the spherical program matches the plane-parallel models in the
high surface gravity regime, and matches spherical models computed by Phoenix
and by MARCS in the low gravity case.Comment: 10 pages, 10 figures, Accepted for publication in A&
Bulk and boundary factorized S-matrices
We investigate the -invariant bulk (1+1D, factorized) -matrix
constructed by Ogievetsky, using the bootstrap on the three-point coupling of
the vector multiplet to constrain its CDD ambiguity. We then construct the
corresponding boundary -matrix, demonstrating it to be consistent with
symmetry.Comment: 7 page
Ignition of thermally sensitive explosives between a contact surface and a shock
The dynamics of ignition between a contact surface and a shock wave is investigated using a
one-step reaction model with Arrhenius kinetics. Both large activation energy asymptotics and
high-resolution finite activation energy numerical simulations are employed. Emphasis is on comparing
and contrasting the solutions with those of the ignition process between a piston and a shock,
considered previously. The large activation energy asymptotic solutions are found to be qualitatively
different from the piston driven shock case, in that thermal runaway first occurs ahead of
the contact surface, and both forward and backward moving reaction waves emerge. These waves
take the form of quasi-steady weak detonations that may later transition into strong detonation
waves. For the finite activation energies considered in the numerical simulations, the results are
qualitatively different to the asymptotic predictions in that no backward weak detonation wave
forms, and there is only a weak dependence of the evolutionary events on the acoustic impedance
of the contact surface. The above conclusions are relevant to gas phase equation of state models.
However, when a large polytropic index more representative of condensed phase explosives is used,
the large activation energy asymptotic and finite activation energy numerical results are found to
be in quantitative agreement
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