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DEPARTMENT OF AERONAUTICAL AND ASTRONAUTICAL ENGINEERING
W. C. Nelson, ChairmanHarm Buning, Acting Chairman,~ Ioq
With the commemoration of its Golden Anniversary in October, 1964, the
Department is entering its second half century of instructional and research
activities in the field of aeronautical and astronautical engineering. During
recent years the curriculum has continued to be modified to keep in step with
the fast changing developments in the aeronautical and aerospace industries.
Fundamental theoretical and experimental studies are carried out in the
,several departmental facilities both on the Central and North Campuses. A
summary of these activities follows.
Aerodynamics Laboratory. The characteristic blunt shape of currently used
reentry bodies has created considerable interest in the nature of the flow
around such bodies. Research is carried out to determine the dynamic
stability of blunt bodies in supersonic as well as in subsonic flows. Some
understanding of these problems is obtained by observing the characteristic
motions and wakes behind disks falling through a liquid (see photographs).
Other studies on this type of body involve measurements of the effect of tur-
bulence on the laminar heat transfer in the stagnation point relion.
In' a study of the behavior of electric arcs in air streams 8uch an arc
with currents up to 1000 amp. was successfully stabilized in a supersonic
flow by means of a crossed magnetic field. The properties of the arc, such
aa current, voltage drop, arc slant, and magnetic field strength, were
measured.
Other experimental studies involve the statistical 8tructure of the unsteady
flow near the wall in a turbulent boundary layer. This work is part of a long-
range 8tudy of boundary layer turbulence, probing into the causes of aircraft
cabin noise and problem8 associated with underwater sonar detection method8.
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Theoretical invet5ti~ations dl~al with the aHvlTlptutk iu\'iscid hypt"rsunic
flow at large distanct's Crf)m a bll1nt budy; th(.. viscuus hypt.rt4onic Wakt' im-
mediately downstr~an1 of a sh'nd~' r C(.IO~; r(.laxat ion pht'non\rna of dilute
plasmas; and the struC"tlll'e of weak curved shockwavl's.
Information and Control Engint'ering. 1'ht~ rt'st'arch activitit.s of the stafC
include the areas of contrul theory. systemR random process theory. data
communication. telemetry. and the general desiqn and applicath>n oC analog
and hybrid cornputt-rs (lo~ic control~ed analog computers) to broad arf!as
including automatic and manual control. strl1ctu\-al dynamic~. non1in~~r- ,
systems. and simulation of airc raft and sP,"CEf ve'bi~~.r.IJ. Rest.arch in co~ts:ol,.. . :~~ ... -. -
is principally in th('. cu~:r nt1 y ac-tivlo a rea: of optimal r'ont rul theory and- compu-
tational methods. The area of application is very broad and includt's at'rospaceo
systems.
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Propulsion l.abnratory. "h~ staff c::ontinues its {undamt'ntal Rtudies of detona-
tive combustion process.'s. This general art'a of study is prompted by com-
bustion. i'1stai)ility p:roblem~' in liqui~ propellant rp~~ttt :q1otors.. w~~hcan,.. ~': ,9__.,." _ .~,, "f' _ "_ - _, . - _ .0:'" to , '~. . -,.
result in de,s~rU(:*ion of tile anotorrand the resulting failure of a mission.
Specifically. one t.heoretical and experimental program involves tbe investiga-
tiol\. of steep press.urf! waves passing 9ve1\ liquid fuel drops i~ a surro~nding. , J) . "! ..
la8~ous oxidizer. Here it is important- to asse""s the influence of the resulting- , . ...'. ',,'
. combustion' on ,the ~hockwave as this inay be the main cOf1tributing factor to
combustion instability. Another phas80f this work concerns itself with. the
details of an interaction between the.- detonation wave and the surrounding
compressible medium.
Modern and future propulsive devices involve the simultaneous flow of
liquid or solid particles with the gas phase. Theoretical and experimental
studies are underway to investigate the differences in velocity and temperature
between particles and gas and the resulting affect on the performance. The
problem is also pertinent to the radiation {rom rocket exhausts and the wakes
-=-=--- -or-hype-r-some reentry bodte-s-.- -.- ,-. --
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In high velocity wind tunnels and in certain types of space rocket motors
and power generators there is the problem of gases condensing to liquids
or solids. Information with regard to the rate of condensation is required.
Studies of these phenomena are being conducted in an arc-discharge hyper-
sonic wind tunnel along with theoretical studie s utilizing advanced digital
computers.
The structure of rocket exhausts at very high altitude is an important
problem from the standpoint of heating the rocket base. communication with
and detection of the rocket. This problem area is being studied spectro-
graphically in the laboratory using a DC arc-generated jet. Theoretical
studies are in progress which seek to account for the particle-like nature
of the gas flow at the very low pressures realized.
Extensive space endeavors and the requirement for higher temperature
aerodynamic facilities has led to the need for an understanding of the energy
exchange processes between an electric arc and gases. Toward this end a
fundamental study of the heat conduction from an alternating current arc to
the surrounding gas flow is being conducted. Also, efforts are being expended
to increase the operating level of a 3-phase AC arc heater to higher tempera-
tures and pressures as a potential source for an hypersonic wind tunnel.
High Altitude Engineering Laboratory. The staff of this laboratory is con-
tinuing its work in aeronomy and high altitude radiation investigations. The
research activities led to the firings of sounding rockets at such far-flung
locations as Fort Churchill. Kwajalein. and from aboard .he USNS Croatan
at southern latitude s. Firings were also carried out at Wallops Island,
Pacific Missile Range and Keweenaw Point. Michigan.
The experimental program of research on atmospheric radiation processes
included aircraft and balloon flight tests of the NIMBUS high and medium
resolution infrared radiometers, which were accepted as payloads on the
NIMBUS and TIROS satellites to be launched later this year. Laboratory
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work involved the development ofa technique to calibrate radiometers in the-I
spectral range 0.4 to 4 microns. A high resolution (5 cm ) infrared inter-
ferometer is being developed for Fourier spectroscopy investigations of
planetary atmospheres. The theoretical program includes studies of radia-
tive heating and cooling in the stratosphere and mesosphere and the deter-
mination of atmospheric temperature structure from satellite radiation
measurements.
The major effort of the aeronomy program is the measurement. in
sounding rocket experiments, oJ the neutral composition to 200 km with a
massenfilter-type mass spectrometer. The quadrupole mass spectrometer,
adapted for longtime satellite usage, has been accepted for installation on
the Polar Orbiting Geophysical Observatory, the first one of which is to be
launched in the summer of 1965.
The refraction technique program is involved in the evaluation of the
operational capability of an instrument for a meteorological satellite. which
measures the refraction of starlight as viewed through the atmosphere from
which density, temperature and pressure can be inferred.
In the area of structural mechanic sand aeroelasticity the primary research
interests are panel flutter and nonlinear vibrations. Both problems have be-
come important because of the large degree of flexibility of modern aerospace
structures prompted by the necessity of minimum weight design. Panel
flutter can occur in the outer surfaces of such vehicles when they encounter
large dynamic pressures in the supersonic flight range. Nonlinear vibration
analysis is dictated by large amplitude motion which may occur.
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