THEORETICAL GROUNDS FOR ANGULAR CORRECTION OF THE SUPPLY AIR JET FLOW VECTOR IN THE VENTILATION SYSTEMS OF INDUSTRIAL AND AGRICULTURAL FACILITIES

2021 ◽  
pp. 20-24
Author(s):  
VIKTOR N. OZHERELYEV ◽  
Keyword(s):  
Inclination Angle ◽  
Three Dimensional ◽  
Control Unit ◽  
Climate Control ◽  
Axisymmetric Jet ◽  
Air Jet ◽  
Time Period ◽  
Free Air ◽  
Angular Correction ◽  
The Relationship

During the heating period, the supply air temperature is lower than that in industrial premises, and the cooled air is denser. Entering a warm room, it tends to move downward. This condition leads to the formation of chilled and stagnant zones. The article presents a theoretical study on the possibility of ensuring the maximum propagation range of a non-isothermal supply air jet by angular correction of the fl ow vector at the outlet of the ventilation unit. Based on the theory of free air distribution, the author analyzed and graphically visualized the fl ow trajectories of the supply air from the combined climate control unit with heat recovery in the production room in the range of outdoor temperatures from +10 to –40°C. Given the time period of outdoor temperatures, fl at sections of a three-dimensional graph were built with a step of 10°C in the range from +10 to –30°C. The author found that the maximum service area of the installation is limited by the propagation range of the supply air jet. The area can be increased by changing the direction of the fl ow vector by an angle ranging between 0 and 34°. The value of the inclination angle of the fl ow vector of the supply air jet is determined by the obtained approximation dependency. Considering the regulation of the fl ow vector, the author used the formula of M.Z. Pechatnikov to determine the propagation range of a limited axisymmetric jet. The studies carried out made it possible to establish the relationship between the propagation range of the supply air jet of the installation and the outside temperature, the inclination angle of the fl ow vector, and the theoretical variation range of the inclination angle of the fl ow vector, ranging between 0 and 34°.

THEORETICAL GROUNDS FOR ANGULAR CORRECTION OF THE SUPPLY AIR JET FLOW VECTOR IN THE VENTILATION SYSTEMS OF INDUSTRIAL AND AGRICULTURAL FACILITIES

2021 ◽  
pp. 25-30
Author(s):  
IVAN YU. IGNATKIN ◽  
Keyword(s):  
Inclination Angle ◽  
Three Dimensional ◽  
Control Unit ◽  
Climate Control ◽  
Axisymmetric Jet ◽  
Air Jet ◽  
Time Period ◽  
Free Air ◽  
Angular Correction ◽  
The Relationship

During the heating period, the supply air temperature is lower than that in industrial premises, and the cooled air is denser. Entering a warm room, it tends to move downward. This condition leads to the formation of chilled and stagnant zones. The article presents a theoretical study on the possibility of ensuring the maximum propagation range of a non-isothermal supply air jet by angular correction of the fl ow vector at the outlet of the ventilation unit. Based on the theory of free air distribution, the author analyzed and graphically visualized the fl ow trajectories of the supply air from the combined climate control unit with heat recovery in the production room in the range of outdoor temperatures from +10 to –40°C. Given the time period of outdoor temperatures, fl at sections of a three-dimensional graph were built with a step of 10°C in the range from +10 to –30°C. The author found that the maximum service area of the installation is limited by the propagation range of the supply air jet. The area can be increased by changing the direction of the fl ow vector by an angle ranging between 0 and 34°. The value of the inclination angle of the fl ow vector of the supply air jet is determined by the obtained approximation dependency. Considering the regulation of the fl ow vector, the author used the formula of M.Z. Pechatnikov to determine the propagation range of a limited axisymmetric jet. The studies carried out made it possible to establish the relationship between the propagation range of the supply air jet of the installation and the outside temperature, the inclination angle of the fl ow vector, and the theoretical variation range of the inclination angle of the fl ow vector, ranging between 0 and 34°.

scholarly journals Estimation of three-dimensional crustal movements in the 2011 Tohoku-oki, Japan earthquake from TerraSAR-X intensity images

2014 ◽  
Vol 2 (12) ◽  
pp. 7383-7408
Author(s):  
W. Liu ◽  
F. Yamazaki ◽  
M. Matsuoka ◽  
T. Nonaka ◽  
T. Sasagawa
Keyword(s):  
Three Dimensional ◽  
Short Time Period ◽  
Sar Images ◽  
Crustal Movements ◽  
Surface Displacements ◽  
Time Period ◽  
Intensity Images ◽  
Short Time ◽  
The Relationship ◽  
Gps Observations

Abstract. The Tohoku-Oki earthquake on 11 March 2011 caused significant widespread crustal movements. In a previous study, we proposed a method for capturing two-dimensional (2-D) surface displacements from a pair of pre- and post-event TerraSAR-X (TSX) intensity images. However, it is difficult to detect three-dimensional (3-D) displacements from one pair of TSX images. In this study, three pairs of pre- and post-event TSX images taken on different paths were used to estimate 3-D crustal movements. The relationship between the actual 3-D displacements and the converted 2-D movements in the SAR images was derived based on the observation model of a SAR sensor. The 3-D movements were then calculated from three sets of detected 2-D movements that occurred within a short time period. Compared with GPS observations, the proposed method was found to be capable of detecting the 3-D crustal movements with sub-pixel accuracy.

scholarly journals Estimation of three-dimensional crustal movements in the 2011 Tohoku-Oki, Japan, earthquake from TerraSAR-X intensity images

2015 ◽  
Vol 15 (3) ◽  
pp. 637-645 ◽  
Author(s):  
W. Liu ◽  
F. Yamazaki ◽  
M. Matsuoka ◽  
T. Nonaka ◽  
T. Sasagawa
Keyword(s):  
Three Dimensional ◽  
Synthetic Aperture ◽  
Sar Images ◽  
Crustal Movements ◽  
Surface Displacements ◽  
Time Period ◽  
Intensity Images ◽  
Short Time ◽  
The Relationship ◽  
Gps Observations

Abstract. The Tohoku-Oki earthquake on 11 March 2011 caused significant widespread crustal movements. In a previous study, we proposed a method for capturing two-dimensional (2-D) surface displacements from a pair of pre- and post-event TerraSAR-X (TSX) intensity images. However, it is impossible to detect three-dimensional (3-D) displacements from one pair of TSX images. In this study, three pairs of pre- and post-event TSX images taken on different paths were used to estimate 3-D crustal movements. The relationship between the actual 3-D displacements and the converted 2-D movements in the synthetic-aperture radar (SAR) images was derived based on the observation model of a SAR sensor. The 3-D movements were then calculated from three sets of detected 2-D movements that occurred within a short time period. Compared with GPS observations, the proposed method was found to be capable of detecting the 3-D crustal movements with sub-pixel accuracy.

Organized motions in a fully developed turbulent axisymmetric jet

1989 ◽  
Vol 203 ◽  
pp. 425-448 ◽  
Author(s):  
Jin Tso ◽  
Fazle Hussain
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Small Scale ◽  
Shear Strain Rate ◽  
Helical Structures ◽  
Vortical Structures ◽  
Axisymmetric Jet ◽  
Air Jet ◽  
Scale Turbulence ◽  
Structure Configuration

An experiment has been conducted to study the occurrence, configuration and dynamics of large-scale coherent vortical motions in the fully developed region of a turbulent axisymmetric jet. The key idea is to use vorticity signals from a spatial grid to detect and sample large-scale vortical structures and then use the (smoothed) vorticity peaks of spatial vorticity patterns to align and ensemble average successive realizations to determine structure configuration and dynamics. Measurements were made in an air jet at ReD = 69000 by employing a radial rake of seven × -wires to obtain the azimuthal vorticity map. Two additional conditioning probes were placed ± 90° away from the rake to determine the three-dimensional phase and hence the structure configuration. Structures with axisymmetric, helical and double helical configurations have been educed. Among them, the helical structures are far more dominant than the others, and the jet dynamics are thus discussed in terms of these helical structures. Helical structures move radially outward as they advect downstream. This radial movement, in conjunction with simultaneous local ejection of turbulent fluid and subsequent entrainment of the ejected fluid with ambient fluid, appears to be a major means of jet spreading. The shear strain rate is strong on the downstream side of the structure, causing intense small-scale turbulence production and mixing there.

Burn-In Acceleration Considerations in 130nm and 90nm Products

2005 ◽  
Author(s):  
Nobuyuki Wakai ◽  
Yuji Kobira ◽  
Takashi Setoya ◽  
Tamotsu Oishi ◽  
Shinichi Yamasaki
Keyword(s):  
Failure Analysis ◽  
Shape Parameter ◽  
Defect Density ◽  
Failure Mechanisms ◽  
Effective Procedure ◽  
Time Period ◽  
Related Defect ◽  
The Relationship

Abstract An effective procedure to determine the Burn-In acceleration factors for 130nm and 90 nm processes are discussed in this paper. The relationship among yield, defect density, and reliability, is well known and well documented for defect mechanisms. In particular, it is important to determine the suitable acceleration factors for temperature and voltage to estimate the exact Burn- In conditions needed to screen these defects. The approach in this paper is found to be useful for recent Cu-processes which are difficult to control from a defectivity standpoint. Performing an evaluation with test vehicles of 130nm and 90nm technology, the following acceleration factors were obtained, Ea>0.9ev and β (Beta)>-5.85. In addition, it was determined that a lower defect density gave a lower Weibull shape parameter. As a result of failure analysis, it is found that the main failures in these technologies were caused by particles, and their Weibull shape parameter “m” was changed depending of the related defect density. These factors can be applied for an immature time period where the process and products have failure mechanisms dominated by defects. Thus, an effective Burn-In is possible with classification from the standpoint of defect density, even from a period of technology immaturity.

Disorganization of a hole tone feedback loop by an axisymmetric obstacle on a downstream end plate

2014 ◽  
Vol 757 ◽  
pp. 908-942 ◽  
Author(s):  
K. Matsuura ◽  
M. Nakano
Keyword(s):  
Nozzle Exit ◽  
Passive Control ◽  
Control Method ◽  
Three Dimensional ◽  
Acoustic Power ◽  
Shear Layers ◽  
Mean Velocity ◽  
End Plate ◽  
Air Jet ◽  
Practical Engineering

AbstractThis study investigates the suppression of the sound produced when a jet, issued from a circular nozzle or hole in a plate, goes through a similar hole in a second plate. The sound, known as a hole tone, is encountered in many practical engineering situations. The mean velocity of the air jet $\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}u_0$ was $6\text {--}12\ \mathrm{m}\ {\mathrm{s}}^{-1}$. The nozzle and the end plate hole both had a diameter of 51 mm, and the impingement length $L_{im}$ between the nozzle and the end plate was 50–90 mm. We propose a novel passive control method of suppressing the tone with an axisymmetric obstacle on the end plate. We find that the effect of the obstacle is well described by the combination ($W/L_{im}$, $h$) where $W$ is the distance from the edge of the end plate hole to the inner wall of the obstacle, and $h$ is the obstacle height. The tone is suppressed when backflows from the obstacle affect the jet shear layers near the nozzle exit. We do a direct sound computation for a typical case where the tone is successfully suppressed. Axisymmetric uniformity observed in the uncontrolled case is broken almost completely in the controlled case. The destruction is maintained by the process in which three-dimensional vortices in the jet shear layers convect downstream, interact with the obstacle and recursively disturb the jet flow from the nozzle exit. While regions near the edge of the end plate hole are responsible for producing the sound in the controlled case as well as in the uncontrolled case, acoustic power in the controlled case is much lower than in the uncontrolled case because of the disorganized state.

scholarly journals Dynamics of Single Droplet Splashing on Liquid Film by Coupling FVM with VOF

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 841
Author(s):  
Yuzhen Jin ◽  
Huang Zhou ◽  
Linhang Zhu ◽  
Zeqing Li
Keyword(s):  
Liquid Film ◽  
Weber Number ◽  
Stokes Equations ◽  
Numerical Study ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Single Droplet ◽  
Navier Stokes Equations ◽  
Volume Method ◽  
The Relationship

A three-dimensional numerical study of a single droplet splashing vertically on a liquid film is presented. The numerical method is based on the finite volume method (FVM) of Navier–Stokes equations coupled with the volume of fluid (VOF) method, and the adaptive local mesh refinement technology is adopted. It enables the liquid–gas interface to be tracked more accurately, and to be less computationally expensive. The relationship between the diameter of the free rim, the height of the crown with different numbers of collision Weber, and the thickness of the liquid film is explored. The results indicate that the crown height increases as the Weber number increases, and the diameter of the crown rim is inversely proportional to the collision Weber number. It can also be concluded that the dimensionless height of the crown decreases with the increase in the thickness of the dimensionless liquid film, which has little effect on the diameter of the crown rim during its growth.

scholarly journals A Field Measurement Based Wind Characteristics Analysis of a Typhoon in Near-Ground Boundary Layer

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 873
Author(s):  
Dandan Xia ◽  
Liming Dai ◽  
Li Lin ◽  
Huaifeng Wang ◽  
Haitao Hu
Keyword(s):  
Turbulence Intensity ◽  
Field Measurement ◽  
Three Dimensional ◽  
Wind Data ◽  
Statistical Characteristics ◽  
Gust Factor ◽  
Characteristics Analysis ◽  
Wind Characteristics ◽  
The Mean ◽  
The Relationship

The field measurement was conducted to observe the wind field data of West Pacific typhoon “Maria” in this research. With the application of ultrasonic anemometers installed in different heights (10 m, 80 m, 100 m) of the tower, the three dimensional wind speed data of typhoon “Maria” was acquired. In addition, vane-type anemometers were installed to validate the accuracy of the wind data from ultrasonic anemometers. Wind characteristics such as the mean wind profile, turbulence intensity, integral length scale, and wind spectrum are studied in detail using the collected wind data. The relationship between the gust factor and turbulence intensity was also studied and compared with the existing literature to demonstrate the characteristics of Maria. The statistical characteristics of the turbulence intensity and gust factor are presented. The corresponding conclusion remarks are expected to provide a useful reference for designing wind-resistant buildings and structures.

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