1,175 research outputs found
Monoposto racecar wheel aerodynamics: investigation of near-wake structure and support-sting interference
No full textMonoposto racecar development is routinely carried out using wheels supported not by the car
suspension but by individual, externally-mounted stings. The interference effect of these stings
was acknowledged but unquantified in the existing literature. Appraisal of the literature has
found that the structure of a wheel wake was not understood, rendering it difficult to assess the
support sting interference. These two issues were thus jointly addressed using experimental and
computational methods.
The two phases of this project each tested a different industrially-representative racecar wheel
model. Phase One investigated a single wheel and sting combination, whilst Phase Two extended
the work to include two further stings and a model racecar. Non-intrusive velocity measurements
were made in the near wakes of the various combinations to extract vertical planes, perpendicular
to the tunnel freestream.
The measurements made behind the isolated wheels were used to investigate the main flow
features of the wake. The flow surrounding an unsupported wheel was established computationally
and used to evaluate the interference effects of the support sting. Different wheel support
methods (three stings and the car suspension) were used to provide further insight into the sting
interference effects and also the impact of sting design on those effects. Testing with and without
the model racecar allowed evaluation of its effect on the wheel wake and sting interference.
The main characteristics of the near-wake of an isolated wheel rotating in ground contact are
proposed from analysis of the data generated in this study. A simplified model of the trailingvortex
system induced in the wake of such a wheel is proposed to clarify contradictory literature.
The specific interference effects of a wheel support sting are proposed with reference to the main
characteristics of the wake. The mechanisms behind these effects are, where possible, identified
and presented. The main impact of the support sting, and thus the root of several of the observed
effects, is the modification of the axial flow through the wheel.
The main effects of the presence of the car on the near-wake are proposed alongside the observation
that the wake structure is not fundamentally different to that of an isolated wheel. The
proposed sting interference effects are also observed in the presence of the car, albeit at a reduced
level
Ric Knowles
No full textRic Knowles holding his three new publications; "Afrika Solo", "Theatre and Interculturalism", and "Asian Canadian Theatre" at the Campus Author Recognition Program Annual Reception, October 27, 2011
고유전율 세라믹 커패시터 조성물
No full textThere is disclosed a high dielectric ceramic composition for capacitors, which comprises (1-x)Pb(Fe.sub.1/2 Ta.sub.1/2)O.sub.3 xPb(Fe.sub.1/2 Nb.sub.1/2)O.sub.3 wherein 0.35.ltoreq.x.ltoreq.0.65, and 0.01-0.5 % by weight of manganese, chromium or cobalt. The composition can be sintered at a temperature of 1,000.degree. C. with a high dielectric constant and a low dielectric loss coefficient
고유전체 세라믹 조성물
No full textDisclosed is a high dielectric capacitor composition consisting of Pb(Fe1/2Nb1/2)O3, Pb(Fe1/2Ta1/2)O3, Pb(Ni1/3Nb2/3)O3 and Pb(Zn1/3Nb2/3)O3 in association with manganese nitrate (Mn(NO3)2.4H2O). It has a dielectric constant of 10,000 or higher with a relatively low loss factor of 2.6% or less, showing the temperature properties of Y5V
The aerodynamic interference effects of side walll proximity on a generic car model
No full textThe flow around a generic car model both in isolation and in proximity to a near side wall has
been investigated utilising experimental and computational methods.
Phase one of this investigation tested a range of Ahmed generic road vehicle models with
varying backlight angles in isolation, employing laser-Doppler anemometry, static pressure
and aerodynamic force and moment measurements in the experimental section. Additionally,
numerical simulations were conducted using a commercial Reynolds-averaged Navier Stokes
(RANS) code with the RNG k-ε turbulence model. This phase served both to extend the
previous knowledge of the flow around the Ahmed model, and analyse the effects of both the
supporting strut and rolling road. Phase two then used similar methods to investigate the
Ahmed model in proximity to a non-moving side wall.
Results from phase two are compared with previous near-wall studies in order that an
understanding of the effects of wall proximity can be presented, an area lacking in the existing
literature.
It is found that the flow on the isolated model must be understood before the effects of side
wall proximity can be assessed. There is though, in general, a breakdown of any longitudinal
vortices on the near-wall side of the model as model-to-wall distance reduces, with an
increase in longitudinal vortex strength on the model side away from the wall. There also
exists a large pressure drop on the near-wall model side, which increases in magnitude as
model-to-wall distance reduces, before dissipating at separations where the boundary layer
restricts the flow.
Additionally, there is found to be a pressure drop on the top and bottom of the model with
decreasing wall distance, with the relative magnitudes of these dependent on model
geometry
Industrial relations in New Zealand: where now?: proceedings of the 25th Anniversary Seminar of the Industrial Relations Centre, held at Victoria University of Wellington, 14 November 1995
No full textKeynote address / Max Bradford -- Industrial relations in New Zealand -retrospect and prospect: a personal view / Kevin Hince -- The view from the New Zealand Employers Federation / Anne Knowles -- The view from the New Zealand Council of Trade Unions / Peter Harris -- Employment law and specialist employment institutions in prospect / Thomas Goddard -- Alumnus view 1 / Ian Powell -- Alumnus view 2 / Graeme Norton -- Alumnus view 3 / Sue Christie -- Alumnus view 4 / Gay Simpkin -- Alumnus view 5 / Bryan Wadsworth -- Alumnus view 6 / Sharon KInsey -- Alumnus view 7 / Mike Feely -- Closing remarks / F.J.L. Young -- Industrial relations in Fiji: where now? / Jo Nacol
An Account of the expedition to Carthagena : with explanatory notes and observations.
No full textAuthorship attributed to Captain (afterwards Admiral) Sir Charles Knowles. cf. Dict. nat. biog., v. 58, p. 272.Expedition of Admiral Vernon and General Wentworth.Mode of access: Internet
Introduction to Aerial Vehicle Flight Mechanics, Stability and Control
No full textThis article provides an introduction to Section 5.1 on flight mechanics and
dynamics, stability and control, and navigation. It introduces some basic
concepts of flight control, and static and dynamic stability. Some particular
features of vertical or short take-off and landing (V/STOL) aircraft flight
control, not covered elsewhere in this Section, are discussed briefly. The other
articles in this Section are introduced
Experimental and computational studies of factors affecting impinging jet flowfields
No full textAn experimental and computational study was made of a single circular jet
impinging onto a flat ground board. A 1/2" nozzle running at a fixed nozzle pressure ratio
of 1.05 was used in the experimental phase (giving an nozzle exit Reynolds number of
90xlO'), the nozzle to ground plane separation being varied between 2 and 10 nozzle
diameters. Measurements were performed in the free and wall jets using single and
cross-wire hot-wire anemometry techniques and pitot pressure probes in order to
detemine mean velocity and normal and shear stress distributions. Some analysis is also
presentedo f earlier measurementso n high pressurer atio impinging jets.
Nozzle height was found to effect the initial thickness of the wall jet leaving the
impingement region, increasing nozzle to ground plane separation increasing the wall jet
thickness, although this separation distance did not seem to affect the rate at which the
wall jet grew. Nozzle height was also found to have a large effect on the peak level of
turbulence found in the wall jet up to a radial distan ce from the jet axial centre line of
4.5 nozzle diameters, after which the profiles become self-similar. Lowering the nozzle
tended to increase the peak level measured in all the turbulent stresses within this
development region. The production of turbulent kinetic energy in the wall jet, which is
an indication of the amount of work done against the mean flow by the turbulent flow
was found to increase dramatically with decreasing nozzle height. This was attributed to
greater shearing of the flow at lower nozzle heights due to a thinner wall jet leaving the
impingement region. A moving impingement surface was found to cause separation of
the wall jet inner boundary layer on the 'approach' side leading to very rapid decay of
peak velocity. The point of separation was found to occur at radial positions in the
region of 7.0 to 8.0 nozzle diameters, this reducing slightly for lower nozzle heights.
A parametric investigation was performed using the k-e turbulence model and the
PHOENICS CFD code. It was found that due to inadequacies in the model, it failed to
predict accurately the growth of the wall jet, both in terms of its initial thickness and the
rate of growth. It did, however, predict an increase in wall jet thickness with both increasing nozzle height and exit turbulence intensity and decreasing nozzle pressure
ratio. Modifications were made to the constants in the model to try and improve the
predictions,w ith a limited degreeo f successT. he low Reynoldsn umber k-F-t urbulence
model was shown to give a slightly improved non-dimensional wall jet profile, although
this did not improve the predicted rate of growth of the wall jet
An Account of the expedition to Carthagena, with explanatory notes and observations.
No full textAuthorship attributed to Captain (afterwards Admiral) Sir Charles Knowles. cf. Dict. nat. biog., v. 58, p. 272.Expedition of Admiral Vernon and General Wentworth.On verso of half title: "See the plan of the city and harbour of Carthagena, published in the London magazine for April 1740; which will serve to give the readers of this pamphlet a clearer idea of its contents."Mode of access: Internet
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