1,269 research outputs found
Attractive internal wave patterns
This paper gives background information for the fluid dynamics video on
internal wave motion in a trapezoidal tank.Comment: 2 pg, movie at two resolutions _low(Low-resolution) and
_hr(High-resolution
Attractive internal wave patterns
This paper gives background information for the fluid dynamics video on
internal wave motion in a trapezoidal tank.Comment: 2 pg, movie at two resolutions _low(Low-resolution) and
_hr(High-resolution
Is a Specialist Employment Court a Better Forum for women?
A series of seminars on "Women and Employment" were held at Victoria University of Wellington in July 1997. The topic of the seminar was whether a specialist employment court is a better forum for women. The following article is based on Maxine Gay's speech at the seminar. She believes that although the Employment Court may have made gender biased decisions, the Court should nevertheless be retained. She argues that a specialist employment court is important for women because it recognises that the employment contract is one in which the parties have unequal power and it should therefore be treated differently from other contracts. She takes the view that the suggestion by the Business Round Table and Employers' Federation to abolish the Employment Court is part of a wider agenda to casualise the labour force and reduce the rights of employees. 
A pattern matching technique for measuring sediment displacement levels
This paper describes a novel technique for obtaining accurate, high (spatial) resolution measurements of sediment redeposition levels. A sequence of different random patterns are projected onto a sediment layer and captured using a high-resolution camera, producing a set of reference images. The same patterns are used to obtain a corresponding sequence of deformed images after a region of the sediment layer has been displaced and redeposited, allowing the use of a high-accuracy pattern matching algorithm to quantify the distribution of the redeposited sediment. A set of experiments using the impact of a vortex ring with a glass ballotini particle layer as the resuspension mechanism are described to test and illustrate the technique. The accuracy of the procedure is assessed using a known crater profile, manufactured to simulate the features of the craters observed in the experiments
Three-dimensional advective--diffusive boundary layers in open channels with parallel and inclined walls
We study the steady laminar advective transport of a diffusive passive scalar
released at the base of narrow three-dimensional longitudinal open channels
with non-absorbing side walls and rectangular or truncated-wedge-shaped
cross-sections. The scalar field in the advective--diffusive boundary layer at
the base of the channels is fundamentally three-dimensional in the general
case, owing to a three-dimensional velocity field and differing boundary
conditions at the side walls. We utilise three-dimensional numerical
simulations and asymptotic analysis to understand how this inherent
three-dimensionality influences the advective-diffusive transport as described
by the normalised average flux, the Sherwood or Nusselt numbers for mass
or heat transfer, respectively. We show that is well approximated by an
appropriately formulated two-dimensional calculation, even when the boundary
layer structure is itself far from two-dimensional. This important result can
significantly simplify the modelling of many laminar advection--diffusion
scalar transfer problems: the cleaning or decontamination of confined channels,
or transport processes in chemical or biological microfluidic devices
Evolution of the Leading-Edge Vortex over an Accelerating Rotating Wing
AbstractThe flow field over an accelerating rotating wing model at Reynolds numbers Re ranging from 250 to 2000 is investigated using particle image velocimetry, and compared with the flow obtained by three-dimensional time-dependent Navier-Stokes simulations. It is shown that the coherent leading-edge vortex that characterises the flow field at Re~200-300 transforms to a laminar separation bubble as Re is increased. It is further shown that the ratio of the instantaneous circulation of the leading-edge vortex in the accel-eration phase to that over a wing rotating steadily at the same Re decreases monotonically with increasing Re. We conclude that the traditional approach based on steady wing rotation is inadequate for the prediction of the aerodynamic performance of flapping wings at Re above about 1000
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