65 research outputs found
On the flow unsteadiness and operational characteristics of a novel supersonic fluidic oscillator
A novel supersonic jet oscillating method is investigated both experimentally
and numerically. A rectangular primary supersonic jet is issued into a confined
chamber with sudden enlargement. Secondary control jets are issued from the
top, and bottom backwards-facing step regions formed due to sudden enlargement.
The secondary jet also expands in the confined chamber shrouding the primary
jet from the top and bottom sides. The primary jet is oscillated in the
transverse direction by blowing the secondary jets in the streamwise direction
in a pulsating manner with a phase shift. The out-of-phase secondary jet
blowing causes the primary jet to periodically adhere to the upper and lower
part of the confined chamber, causing flapping of the primary jet and acting as
a supersonic fluidic oscillator. The supersonic jet oscillation characteristics
are experimentally investigated using shadowgraph type flow visualization
technique and steady and unsteady pressure measurements. Quantitative analysis
of the shadowgraph images using the construction of and plots
reveals the presence of periodic jet oscillation with a discrete dominant
frequency similar to the secondary jet excitation frequency. The existence of
linearity between the excitation frequency and the flapping jet frequency on
the low-frequency ( Hz) side is first proven experimentally. Later,
the high-frequency ( Hz) operation extent of the supersonic fluidic
oscillator is further demonstrated using unsteady computational studies owing
to the existing experimental facility's limitations. It is found from the
computational studies that there exists a limiting oscillation frequency for
the present fluidic oscillator (nearly kHz with the particular
geometric size and the injection momentum considered in the present study).Comment: 11 Figures. Relevant multimedia views and supplementary videos are
embedded in the pdf itself. The article is prepared for submission to Phys.
Fluid
Growth of Silicon- Germanium Alloy Layers
Heteroepitaxy techniques for the growth of group IV binary alloys, in particular, SiGe, SiC, GeC and SiSn films are reviewed. Deposition of heteroepitaxial films using various reactors like molecular beam epitaxy, gas source molecular beam epitaxy, and different chemical vapour deposition techniques are compared. Issues related to heteroepitaxial film deposition, such as critical layer thickness are examined. Growth of strained silicon on relaxed SiGe buffer layers, poly-SiGe film and hydrogenated amorphous SiGe (a-SiGe:H) film is also reviewe
HfO2/HfAlO/HfO2 nanolaminate charge trapping layers for high-performance nonvolatile memory device applications
Charge trapping characteristics of atomic-layer-deposited HfO2 films with Al2O3 as a blocking oxide for high-density non-volatile memory device applications
Band offsets and charge storage characteristics of atomic layer deposited high-k HfO2/TiO2 multilayers
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