Flow of a falling liquid curtain into a pool

2014 ◽  
Vol 741 ◽  
pp. 350-376 ◽  
Author(s):  
Harumichi Kyotoh ◽  
Kazuki Fujita ◽  
Koichi Nakano ◽  
Takeaki Tsuda
Keyword(s):  
Deflection Angle ◽  
Coanda Effect ◽  
Vertical Flow ◽  
Pool Surface ◽  
Oblique Flow ◽  
Conservation Of Momentum ◽  
Number Flow ◽  
The Deflection Angle ◽  
Simulation Results ◽  
Coandǎ Effect

AbstractWe investigate the low-Weber-number flow of a liquid curtain bridged between two vertical edge guides and a pool surface. Three flow patterns, namely, steady vertical flow, steady oblique flow, and oscillatory oblique flow, are observed in our experiment. These patterns are caused by the Coanda effect of the jet around the meniscus that is formed in the matching region common to the liquid curtain and the pool surface. Here, the deflection angle of the jet is greater than $90^\circ $. The equation describing the motion of the liquid curtain applicable for a finite curtain slope is obtained using the intrinsic coordinate system in which the distance along the curtain is selected as one of the coordinates, and the equation of the meniscus motion is derived by considering the conservation of momentum. The curtain deformations of oblique flows are analysed by generating numerical simulations of these equations, and the simulation results are then compared with experimental results. Also, the period of oscillatory oblique flow is discussed and explained via the response analyses of the curtain, and the result shows that the period of the oscillations is close to that of the most amplified mode of the liquid curtain. Further, the detachment angle of the jet is discussed in relation to the Coanda effect of the jet in the meniscus.

scholarly journals FLUCTUATIONS OF THE CARGO TRANSPORTED BY LIFTING CRANE: SIMULATION AND ANALYSIS

2019 ◽  
Vol 16 (5) ◽  
pp. 526-533
Author(s):  
M. S. Korytov ◽  
V. S. Shcherbakov ◽  
V. E. Belyakov
Keyword(s):  
Objective Function ◽  
Arbitrary Order ◽  
Deflection Angle ◽  
Suspension Point ◽  
Program Code ◽  
First Derivative ◽  
Urgent Task ◽  
Acceleration And Deceleration ◽  
The Deflection Angle ◽  
Simulation Results

Introduction. Reducing fluctuations in the load transported by hoisting cranes with a flexible rope suspension of the load is an urgent task since it can significantly reduce the time taken to complete the operation of moving the load. A promising direction for reducing load fluctuations is to optimize the trajectory of movement of the load suspension upper point.Materials and methods. The paper discussed the method of mathematical simulation of plane vibrations of a load moved by a crane with a horizontally moving suspension point, using the software of the MATLAB system. For modeling, the authors used the function of the MATLAB ode45 system, intended for the numerical solution of systems of non-stationary differential equations of arbitrary order.The second-order differential equation used to describe the fluctuations of the transported load and its implementation in the form of program code was presented. Moreover, the authors demonstrated the elements of program code for the analysis and visualization of simulation results.Results. The authors obtained and presented the series of graphs in the inclination angle’s changing of the cargo rope, the acceleration of the suspension point and the value of the objective function with the sinusoidal nature of the acceleration. The objective function was the sum of the absolute values of the deflection angle of the rope and the first derivative at the final moment of the suspension point’s movement with acceleration.Discussion and conclusions. As a result, the paper shows that the system with energy dissipation does not reach the zero value of the objective function even by a symmetrical nature of acceleration and deceleration of the suspension point. Therefore, it is necessary to give asymmetry to the acceleration and deceleration periods of the suspension point in order to completely absorb the residual fluctuations of the load.

Hysteresis of the Coanda Effect

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Aldona Skotnicka-Siepsiak
Keyword(s):  
Deflection Angle ◽  
Coanda Effect ◽  
Inclined Plate ◽  
Free Jet ◽  
Long Time ◽  
Jet Behavior ◽  
Coandǎ Effect ◽  
New Applications ◽  
Plane Jet ◽  
First Time

For scientist, the Coanda effect has been an object of interest for a long time. All the time, some new applications of it are found although it has been more than a hundred years since Henri Coanda got a patent that was critical for that issue. Apart from aviation, it is more and more often used in ventilation systems to control the manner of air division and the design nozzles and ventilators. It is surprising, however, that a good command of that phenomenon and a need to apply it in different solutions did not entail a significant increase of the interest in the Coanda effect hysteresis, although it was mentioned for the first time by Newman in 1961. This article presents results of experimental measurements for a two-dimensional incompressible plane jet by an inclined plate. The hysteresis has been observed as a different jet behavior (a free jet or a jet attached to a flat plate) depending on the direction in which the plate deflection angle changes. The observed hysteresis area, defined by critical values for the αca attachment and αcd detachment angles, spanned from 8 deg to 14 deg. Its dependency on the Reynolds number has also been examined for Re ranging from 3500 to 26,500. Considering the Coanda effect hysteresis, a pressure distribution on the plate and the xR reattachment distance has been examined. The distribution of forces on a plate has been identified, which has facilitated a graphical mirroring of the Coanda effect hysteresis loop.

The Material Discontinuous Zone Influence on the Behavior of Crack Propagation in the Matrix Material

2013 ◽  
Vol 345 ◽  
pp. 263-267
Author(s):  
Zhi Jia Sun ◽  
You Tang Li
Keyword(s):  
Crack Propagation ◽  
Deflection Angle ◽  
Matrix Material ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Propagation Path ◽  
Propagation Behavior ◽  
The Matrix ◽  
The Deflection Angle ◽  
Simulation Results

A numerical method to simulate the crack propagation is presented in this paper. The FEM is used to estimate the influence of the material discontinuous zone on the propagation behavior of the crack placed in close to it in the matrix. The crack propagation paths in the matrix with different material discontinuous zone are simulated. The simulation results show that the crack propagation path will deviate toward the material discontinuous zone when the crack grows in closed to it and the property of the material discontinuous zone influences the deflection angle and the crack propagation rate.

Influences of Local Micro Impurity on Capillary Jet

2015 ◽  
Vol 731 ◽  
pp. 265-268
Author(s):  
Xiao Shan Jiang ◽  
Ting Liang Chu
Keyword(s):  
Deflection Angle ◽  
Curved Surface ◽  
Local Pressure ◽  
Hypothetical Model ◽  
The Deflection Angle ◽  
Simulation Results ◽  
The Stability

In order to prevent the deflecting jet, a hypothetical model of local micro impurity is proposed to investigate the transformation of capillary jet on the deflection angle, jet direction, and local pressure. The changes are revealed as the local impurity lies at the different places of inner orifice wall. The simulation results agree with the experiments that the capillary jet deflects as the impurity lies in the orifice of capillary nozzle, which proves that the hypothetical model of local micro impurity is reasonable. Cleaning measures are taken to eliminate the jet deflection. This work is useful to improve the direction accuracy and the stability of capillary jet for the subsequent inkjet process in complex curved surface printing.

scholarly journals Quantitative evaluation indexes of the spatial steering effect of directional perforation hydraulic fractures

2021 ◽  
pp. 014459872110102
Author(s):  
Lu Weiyong ◽  
He Changchun
Keyword(s):  
Quantitative Evaluation ◽  
Hydraulic Fracture ◽  
Deflection Angle ◽  
Hydraulic Fractures ◽  
Principal Stress Direction ◽  
Perforation Hole ◽  
Evaluation Indexes ◽  
Initiation Pressure ◽  
The Deflection Angle ◽  
Bending Fracture

To better evaluate the spatial steering effect of directional perforation hydraulic fractures, evaluation indexes for the spatial steering effect are first proposed in this paper. Then, these indexes are used to quantitatively evaluate existing physical experimental results. Finally, with the help of RFPA2D-Flow software, the influence of perforation length and azimuth on the spatial steering process of hydraulic fracture are quantitatively analysed using four evaluation indexes. It is shown by the results that the spatial deflection trajectory, deflection distance, deflection angle and initiation pressure of hydraulic fractures can be used as quantitative evaluation indexes for the spatial steering effect of hydraulic fractures. The deflection paths of directional perforation hydraulic fractures are basically the same. They all gradually deflect to the maximum horizontal principal stress direction from the perforation hole and finally represent a double-wing bending fracture. The deflection distance, deflection angle and initiation pressure of hydraulic fractures increase gradually with increasing perforation azimuth, and the sensitivity of the deflection angle to the perforation azimuth of hydraulic fractures also increases. With increasing perforation length, the deflection distance of hydraulic fractures increases gradually. However, the deflection angle and initiation pressure decrease gradually, as does the sensitivity.

Flow attachment to solid surfaces: The Coanda effect

AIChE Journal ◽  
1972 ◽  
Vol 18 (1) ◽  
pp. 51-57 ◽  
Author(s):  
T. Panitz ◽  
D. T. Wasan
Keyword(s):  
Solid Surfaces ◽  
Coanda Effect ◽  
Coandǎ Effect

scholarly journals Comparison of CFD simulations and measurements of flow affected by coanda effect

2012 ◽  
Vol 25 ◽  
pp. 01015 ◽  
Author(s):  
Jan Fišer ◽  
Jan Jedelský ◽  
Tomáš Vach ◽  
Matěj Forman ◽  
Miroslav Jícha
Keyword(s):  
Coanda Effect ◽  
Cfd Simulations ◽  
Coandǎ Effect

scholarly journals OPERATOR-PRODUCT EXPANSION AND ANALYTICITY

1999 ◽  
Vol 14 (30) ◽  
pp. 4819-4840
Author(s):  
JAN FISCHER ◽  
IVO VRKOČ
Keyword(s):  
Operator Product Expansion ◽  
Deflection Angle ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Operator Product ◽  
Coupling Constant ◽  
Expectation Value ◽  
Euclidean Region ◽  
The Deflection Angle ◽  
Class Of Functions

We discuss the current use of the operator-product expansion in QCD calculations. Treating the OPE as an expansion in inverse powers of an energy-squared variable (with possible exponential terms added), approximating the vacuum expectation value of the operator product by several terms and assuming a bound on the remainder along the Euclidean region, we observe how the bound varies with increasing deflection from the Euclidean ray down to the cut (Minkowski region). We argue that the assumption that the remainder is constant for all angles in the cut complex plane down to the Minkowski region is not justified. Making specific assumptions on the properties of the expanded function, we obtain bounds on the remainder in explicit form and show that they are very sensitive both to the deflection angle and to the class of functions considered. The results obtained are discussed in connection with calculations of the coupling constant αs from the τ decay.

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