scholarly journals Theoretical and practical aspects of the Coandă effect applied in aeronautics

2019 ◽  
Vol 290 ◽  
pp. 06003
Author(s):  
Ionică Cîrciu ◽  
Constantin Rotaru
Keyword(s):  
Flue Gas ◽  
Convex Surface ◽  
Dynamic Effect ◽  
Coanda Effect ◽  
Gas Jets ◽  
Fluid Jets ◽  
Coandǎ Effect ◽  
First Time ◽  
Airplane Fuselage ◽  
Short Flight

The Coandă Effect, or better said, the deviation of fluid jets to stay attached to a convex surface is a complex gas-dynamic effect, named after the Romanian aviation engineer Henri Coandă and it was for the first time highlighted by him in 1910 during the take-off of one of his first planes, Coandă-1910, which was also the first jet plane to fly. During the short flight, Coandă was able to notice the near-fit alignment of the flue gas jets with the airplane fuselage. Later, both Coandă and other scholars have intensively studied the effect that is named The Coandă Effect, in his honor.

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.

Mathematical Modelling of a Two Streams Coanda Effect Nozzle

2013 ◽  
Author(s):  
Michele Trancossi ◽  
Subhash Maharshi ◽  
Diego Angeli
Keyword(s):  
Mathematical Model ◽  
Dynamic Equilibrium ◽  
Convex Surface ◽  
Coanda Effect ◽  
Jet Streams ◽  
Bibliographic Analysis ◽  
Mixing Effect ◽  
Preliminary Validation ◽  
Coandǎ Effect ◽  
Main Component

This paper analyses the ACHEON Coanda effect based propulsion nozzle for aircraft propulsion based on the dynamic equilibrium of two jet streams. It presents a large bibliographic analysis and the ACHEON concept and, in particular, the HOMER Nozzle, that is its main component. The Constructal optimization process that allows defining this architecture has presented. A preliminary mathematical model of a 2D case of the system has presented, focusing on the combined effect of the mixing effect of the two streams and the Coanda Effect Adhesion over a convex surface. A CFD preliminary validation has presented in uncompressible regime. The results have been evaluated in 2D cases.

scholarly journals The influence of convective exchanges on Coandã effect

2019 ◽  
Vol 11 (4) ◽  
pp. 191-202 ◽  
Author(s):  
Michele TRANCOSSI ◽  
Jose PASCOA
Keyword(s):  
Heat Exchange ◽  
Convective Heat ◽  
Convex Surface ◽  
Fluid Dynamic ◽  
Convective Heat Exchange ◽  
Research Direction ◽  
Effective Model ◽  
Coanda Effect ◽  
Cfd Simulations ◽  
Coandǎ Effect

Modeling Coandã effect has been a fundamental issue in fluid dynamic research in the XX century. It has lost some interest because of the improvement in CFD, even if it could be still important in the area of the preliminary design of aerodynamic devices that benefits of fluid deflection by convex surfaces. An effective model of Coandã effect has not been defined, and fundamental questions are still open. The influence of convective heat exchange on Coandã adhesion of a fluid stream on a convex surface in the presence of a temperature gradient between the fluid and the convex surface is a problem, which affects many practical cases, but it is still marginally approached by scientific literature. This paper aims to start an effective research direction on the effects of convective heat exchange on Coandã effect. It approaches the problem with a set of CFD simulations. It analyses the previous hypotheses, which are based on Prandtl number and evidences the need of a more effective model that accounts also for the Reynolds number.

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

Surface Tension Effects on Discharge Capacity of Coanda-Effect Screens

2021 ◽  
Vol 147 (8) ◽  
pp. 04021026
Author(s):  
Tony L. Wahl ◽  
Christopher C. Shupe ◽  
Hajrudin Dzafo ◽  
Ejub Dzaferovic
Keyword(s):  
Surface Tension ◽  
Discharge Capacity ◽  
Coanda Effect ◽  
Coandǎ Effect

Mercury concentrations in thermal waters of the Bolshoi Semyachik hydrothermal system, Russia, Kamchatka.

2021 ◽  
Author(s):  
Anton Nuzhdaev
Keyword(s):  
Hydrothermal System ◽  
Kamchatka Peninsula ◽  
Hydrothermal Systems ◽  
Thermal Waters ◽  
Hydrothermal Solutions ◽  
Average Value ◽  
Thermal Fields ◽  
Gas Jets ◽  
First Time ◽  
Hydrothermal Fields

<p>The study of mercury receipt within volcanic activity zones and large hydrothermal systems recently causes the big interest connected with attempts of an estimation of volumes of natural mercury receipt on a daily surface.</p><p>The hydrothermal system connected with volcanic massif Big Semyachik is one of the largest on the territory of Kamchatka peninsula. On the surface, the hydrothermal system is manifested by three large hydrothermal fields - the Verhnee Field, the parychay Dolina, and the Northern Crater of the Central Semyachik, the heat export from which is estimated at 300 MW (Vakin, 1976). On the surface of the thermal fields hot thermal waters and powerful steam-gas jets are unloaded.  At the same time, due to the inaccessibility of thermal fields remain poorly studied, and in particular, there is no information on the concentrations of mercury in hydrothermal solutions.</p><p>During fieldwork in 2020 all types of thermal waters were sampled, chemical types of waters were established, concentrations of mercury in hydrothermal solutions: for hot thermal waters the average value of mercury was - 0.44 mcg / L, and in steam-gas jets - the average value of mercury was - 4.60 mcg / L.</p><p>Thus, in the course of the work the data on concentrations of mercury in hydrothermal solutions of one of the largest hydrothermal systems of Kamchatka were received for the first time.</p><p> </p>

scholarly journals Theoretical Modeling, Design and Simulation of an Innovative Diverting Valve Based on Coanda Effect

Fluids ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. 103
Author(s):  
Giancarlo Comes ◽  
Carlo Cravero
Keyword(s):  
Fluid Dynamics ◽  
Mathematical Model ◽  
Computational Fluid Dynamics ◽  
Additive Manufacturing ◽  
Water Flow ◽  
Coanda Effect ◽  
Geometrical Parameters ◽  
Convex Wall ◽  
Fluidic Device ◽  
Coandǎ Effect

The present work is focused on the study of an innovative fluidic device. It consists of a two-ways diverter valve able to elaborate an inlet water flow and divert it through one of the two outlets without moving parts but as a result of a fluctuation of pressure induced by two actuation ports, or channels. Such apparatus is named Attachment Bi-Stable Diverter (ABD) and is able to work with the effect of the fluid adhesion to a convex wall adjacent to it, this phenomenon is known as Coanda Effect; it generates the force responsible for the fluid attachment and the consequent deviation. The main purpose of this work is to develop a knowhow for the design and development of such particular device. A mathematical model for the ABD has been developed and used to find the relationships between the geometrical parameters and the operative conditions. A configuration has been designed, simulated with a computational fluid dynamics approach. A prototype has been printed with and additive manufacturing printer and tested in laboratory to check the effective working point of the device.

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