FLOW ANALYSIS OF THE IMPINGEMENT OF A VARIABLE-DIAMETER SYNTHETIC JET

2019 ◽  
Vol 26 (2) ◽  
pp. 127-148
Author(s):  
Alexander J. Zielinski ◽  
Stephen A. Solovitz
Keyword(s):  
Flow Analysis ◽  
Synthetic Jet ◽  
Variable Diameter

Examination of a Variable-Diameter Synthetic Jet

2016 ◽  
Vol 138 (12) ◽  
Author(s):  
Spencer O. Albright ◽  
Stephen A. Solovitz
Keyword(s):  
Particle Image Velocimetry ◽  
Vortex Ring ◽  
Mass Flux ◽  
Particle Image ◽  
Synthetic Jet ◽  
Synthetic Jets ◽  
Variable Diameter ◽  
Constant Diameter ◽  
Image Velocimetry ◽  
Jet Actuators

Synthetic jet actuators are used to produce net axial momentum flow without net mass flux. Through strategic application, such devices can be used for flow control, propulsive thrust, and cooling. A novel application uses a variable-diameter orifice to constrict the exiting flow, and the motion can be synchronized with the pulse of the jet. This device is examined using phase-locked particle image velocimetry (PIV), permitting investigation of the flow fields and momentum flow. When compared to fixed-diameter synthetic jets, the variable-diameter actuator produces a larger vortex ring that lingers nearer the aperture. In addition, the experiments show increased momentum when the aperture is contracted in phase with the pulsing jet, with peak levels more than twice that of a constant-diameter jet.

Fluid Flow Analysis Through a Variable Diameter Infra-Red Suppression Device

2020 ◽  
Vol 17 (1) ◽  
pp. 7734-7748
Author(s):  
Avik Bhattacharya ◽  
A. Madhusudan Achari
Keyword(s):  
Reynolds Number ◽  
Fluid Flow ◽  
High Velocity ◽  
Flow Analysis ◽  
Computational Studies ◽  
The Past ◽  
Variable Diameter ◽  
Infra Red ◽  
Fluid Flow Analysis ◽  
Bidirectional Flow

An Infra-red suppression device(IRS) is used for suppression of heat signatures from the exhaust of the ships or aero planes, thus facilitating in the stealth operation. In the past, studies have been performed on multiple funnel type, lobed shaped as well as straight funnel type IRS device. In the present study an attempt has been made to suggest a variable diameter IRS device which works on the principle of mass suction due to drop in pressure resulting from the high velocity exhaust fluid. The multiple funnel type IRS device has been modified into an inverted fulcrum like device with holes present on the periphery of device for suction of fluid. Two types of computational studies have been performed. In the first study, the suction is occurring through the bottom as well as the holes on the periphery of funnel wall. In the second study, suction is occurring only through the holes on the funnel wall and bottom of funnel has been kept closed. The mass suction ratio has been calculated for varying Reynolds number (3000≤ R ≤ 7000). The effect on suction due to position of holes, number of holes and distance of the holes from the nozzle, effect of bidirectional flow etc. has been computed. It is found that the mass suction ratio is more when suction is occurring through the bottom of the funnel along with the holes on the funnel wall periphery.

Development of a Variable Diameter Synthetic Jet Actuator

2014 ◽  
Author(s):  
Spencer O. Albright ◽  
Stephen A. Solovitz
Keyword(s):  
Synthetic Jet ◽  
Pneumatic Cylinder ◽  
Synthetic Jet Actuator ◽  
Variable Diameter ◽  
Image Velocimetry ◽  
Flow Speeds ◽  
Exit Speed ◽  
Zero Net Mass Flux ◽  
Piston Stroke ◽  
Oscillating Motion

Synthetic jet actuators use oscillating motion near a fixed orifice to produce a net axial momentum flux with zero net mass flux. Through strategic application, these devices can provide flow control, propulsive thrust, and impingement cooling. To improve this performance, a new actuator has been designed with a variable orifice size, which can potentially increase exit flow speeds. The jet is generated using a pneumatic cylinder, which is oscillated linearly near an orifice. The opening consists of a camera aperture, whose diameter can decrease by a factor of 18 with the aid of a second pneumatic cylinder. The system is capable of operating at frequencies up to 5 Hz while maintaining full piston stroke, and the phase between the piston and orifice motion can be varied from 0 to 180 degrees. The flow structure is investigated using phase-locked particle image velocimetry (PIV), which shows that simultaneous constriction of the exit can substantially increase the exit speed. The initial design is used with air flow but will be extended to water applications in the future.

The Laminar Flow Simulation of Variable Diameter GFRP Pipe with Transition Region

2011 ◽  
Vol 366 ◽  
pp. 68-71
Author(s):  
Ya Xuan Wang ◽  
Jing Ji ◽  
Shu Zhang
Keyword(s):  
Finite Element ◽  
Laminar Flow ◽  
Transition Region ◽  
Flow Analysis ◽  
Flow Simulation ◽  
Element Analysis ◽  
Finite Element Software ◽  
Variable Diameter ◽  
Vector Distribution ◽  
Liquid Flows

To investigate the variation rule of fluidic speed in variable diameter GFRP pipe with transition region when the liquid flows through the pipe, the FLOTRAN CFD module of the ANSYS finite element software is adopted to take the laminar flow analysis on 4 diversion pipes with transition region in this paper. The finite element analysis process is introduced in detail, and the velocity vector distribution of the 4 diversion pipes is got. As can be seen from the graph, the velocity of the liquid begins to become quick before the liquid reaches transition region, the velocity of the central liquid is the fastest when the fluid passes the transition zone, the closer the distance is away the wall, the slower the liquid flows, and the distribution is conical basically. 37 degree is recommended in the transition region and it can provide the reference for the turbulent analysis of variable diameter GFRP pipe with transition region.

Ultrastructure of bronchopulmonary lavage cells from bovines administered 3-methylindole: II. 24 hours post-treatment

1984 ◽  
Vol 42 ◽  
pp. 202-203
Author(s):  
Amreek Singh ◽  
Judith M. McLaren ◽  
Onkar S. Atwal ◽  
Peter Eyre
Keyword(s):  
Plasma Cells ◽  
Ciliated Cell ◽  
Lavage Fluid ◽  
Treated Group ◽  
Post Treatment ◽  
Lung Edema ◽  
Ciliated Cells ◽  
Thin Sections ◽  
Variable Diameter ◽  
Cell Pellet

Introduction3-methylindole (MI), a rumen metabolite of the amino acid L-tryptophan, has been shown to produce bovine pulmonary edema and emphysema. The airways contain free and exfoliated cells. A morphologic analysis of these cells may complement the understanding of the mechanism of lung edema. Ultrastructure of the bronchopulmonary lavage (BL) cells 24 h following MI oral administration to calves is described in this experiment. The 12 hours post-treatment results were described earlier.Materials and MethodsTwo Holstein-Friesian calves were each administered an oral dose of 0.2 g MI/Kg body weight and another two calves served as controls. The animals were euthanized with sodium pentabarbitol 24 h after receiving the compound. The lungs and trachea were removed and 0.1 M sodium phosphate buffered saline was infused into the lungs through the trachea. Glutaraldehyde fixative was added to the recovered BL fluid so as to form a 1% solution. The fluid was centrifuged and the resulting cell pellet was suspended in the buffer. The procedures were repeated on the suspension; the pellet was post-fixed in osmium tetroxide and was processed by conventional methods of section preparations for TEM examination. Lung samples from caudal lobes were fixed in 1.5% glutaraldehyde to obtain tissue sections for TEM.Results and DiscussionPulmonary alveolar macrophages (AM), neutrophils, ciliated epithelial cells, globule leukocytes and plasma cells were recovered from the BL fluid of the control and Mi-administered calves. Ciliated cells and globule leukocytes could not be harvested from the controls. The AM obtained from the treated calves (Fig. 1) in comparison with similar cells from the controls were larger, and contained large membrane-limited inclusions (phagolysosomes). There was a remarkable similarity between the lavaged AM and the AM studied in thin sections of lung (cf. Fig. 1 and Fig. 2). The neutrophil was the second most abundant cell type retrieved from the lavage fluid from the calves of control or treated group. Except for scanty pseudopodia in the neutrophils obtained from the Mi-receiving calves, the cells appeared unaltered (Fig. 3). Ciliated cells were abundant in the BL fluid of Mi-ingesting calves. A heterogeneous collection of vesicles filled the ciliated cell cytoplasm (Fig. 3). Globule leukocytes were commonly observed among BL cells of treated calves. The globule leukocytes were ca. 15 μm in diameter and contained round or elliptical nuclei with conspicuous nucleoli. The cytoplasmic granules, which are a prominent feature of globule leukocytes, were electron-opaque and had a variable diameter (0.5-3.0 μm). A one-line account of globule leukocytes in the bronchi of steers administered MI has appeared. Plasma cells were rare. Ultrastructure of BL cells is compatible with their response to chemical insult by MI.

Quantitative Diameter Measurements of Chromatin and TMV Fibers in the Freeze-Dried State

1988 ◽  
Vol 46 ◽  
pp. 170-171
Author(s):  
B. D. Athey ◽  
A. L. Stout ◽  
M. F. Smith ◽  
J. P. Langmore
Keyword(s):  
Reliable Method ◽  
Fiber Diameter ◽  
Quantitative Agreement ◽  
One Dimension ◽  
Fiber Axis ◽  
Two Dimensional ◽  
Fiber Density ◽  
Variable Diameter ◽  
Freeze Dried ◽  
Expected Values

Although there is general agreement that Inactive chromosome fibers consist of helically packed nucleosomes, the pattern of packing is still undetermined. Only one of the proposed models, the crossed-linker model, predicts a variable diameter dependent on the length of DNA between nucleosomes. Measurements of the fiber diameter of negatively-stained and frozen- hydrated- chromatin from Thyone sperm (87bp linker) and Necturus erythrocytes (48bp linker) have been previously reported from this laboratory. We now introduce a more reliable method of measuring the diameters of electron images of fibrous objects. The procedure uses a modified version of the computer program TOTAL, which takes a two-dimensional projection of the fiber density (represented by the micrograph itself) and projects it down the fiber axis onto one dimension. We illustrate this method using high contrast, in-focus STEM images of TMV and chromatin from Thyone and Necturus. The measured diameters are in quantitative agreement with the expected values for the crossed-linker model for chromatin structure

Production flow analysis

1963 ◽  
Vol 42 (12) ◽  
pp. 742 ◽  
Author(s):  
John L. Burbidge
Keyword(s):  
Flow Analysis ◽  
Production Flow

Main Provisions Of The Concept Of Technology Of Diamond Cutting And Drilling Of Building Structures

2019 ◽  
pp. 59-63
Keyword(s):  
Combustion Engine ◽  
Front Surface ◽  
The Body ◽  
Building Structures ◽  
Diamond Cutting ◽  
Variable Diameter ◽  
Diamond Drilling ◽  
Single Structure ◽  
New Construction ◽  
Non Destructive

The main provisions of the concept of technology of diamond cutting and drilling of building structures are considered. The innovativeness of the technology, its main possibilities and advantages are presented. Carrying out works with the help of this technology in underwater conditions expands its use when constructing and reconstructing hydraulic structure. The use of diamond drilling equipment with motors equipped with an internal combustion engine is considered. Drilling holes with a variable diameter during the reconstruction of the runways of airfields makes it possible to combine the landing mats into a single structure. The ability to cut inside the concrete mass, parallel to the front surface, has no analogues among the methods of concrete treatment. The use of this technology for producing blind openings in the body of concrete without weakening the structure is also unique. Work with precision quality in cutting and diamond drilling of concrete and reinforced concrete was noted by architects and began to be implemented in the manufacture of inter-room and inter-floor openings. Non-destructive approach to the fragmentation of building structures allows them to be reused. The technology of diamond cutting and drilling is located at the junction of new construction, repair, reconstruction of buildings and structures, and dismantling of structures. Attention is paid to the complexity and combinatorial application of diamond technology. Economic efficiency and ecological safety of diamond technology are presented. The main directions of further research for the development of technology are indicated.

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