scholarly journals Numerical study of the churn-slug transition dynamics in vertical upward air-water flows

2013 ◽  
Author(s):  
F. H. J. Imada ◽  
F. Saltara ◽  
J. L. Baliño
Keyword(s):  
Numerical Study ◽  
Transition Dynamics ◽  
Water Flows

scholarly journals Numerical Study of Turbulent Air and Water Flows in a Nozzle Based on the Coanda Effect

2019 ◽  
Vol 7 (2) ◽  
pp. 21
Author(s):  
Youssef El Halal ◽  
Crístofer Marques ◽  
Luiz Rocha ◽  
Liércio Isoldi ◽  
Rafael Lemos ◽  
...  
Keyword(s):  
Mass Flow ◽  
High Speed ◽  
Numerical Study ◽  
Fluid Dynamic ◽  
Working Fluid ◽  
Coanda Effect ◽  
Water Flows ◽  
Operational Principle ◽  
Coandǎ Effect ◽  
Marine Applications

In the present work it is performed a numerical study for simulation of turbulent air and water flows in a nozzle based on the Coanda effect named H.O.M.E.R. (High-Speed Orienting Momentum with Enhanced Reversibility). The main purposes of this work are the development of a numerical model for simulation of the main operational principle of the H.O.M.E.R. nozzle, verify the occurrence of the physical principle in a device using water as working fluid and generate theoretical recommendations about the influence of the difference of mass flow rate in two inlets and length of septum over the fluid dynamic behavior of water flow. The time-averaged conservation equations of mass and momentum are solved with the Finite Volume Method (FVM) and turbulence closure is tackled with the k-ε model. Results for air flow show a good agreement with previous predictions in the literature. Moreover, it is also noticed that this main operational principle is promising for future applications in maneuverability and propulsion systems in marine applications. Results obtained here also show that water jets present higher deflection angles when compared with air jets, enhancing the capability of impose forces to achieve better maneuverability. Moreover, results indicated that the imposition of different mass flow rates in both inlets of the device, as well as central septum insertion have a strong influence over deflection angle of turbulent jet flow and velocity fields, indicating that these parameters can be important for maneuverability in marine applications.

Numerical Investigation of Natural Convection Characteristics in a Water Tank

2012 ◽  
Author(s):  
Fariborz Karimi Talkhoncheh ◽  
Jinlong Wang ◽  
Hongtao Xu ◽  
Mo Yang ◽  
Yuwen Zhang
Keyword(s):  
Nusselt Number ◽  
Natural Convection ◽  
Numerical Study ◽  
Horizontal Cylinder ◽  
Hot Water ◽  
Cylinder Surface ◽  
Water Tank ◽  
Tank Model ◽  
Water Flows ◽  
Aspect Ratios

In this paper, the numerical study is performed to investigate the natural convection characteristics in a 2D water tank model. The hot water flows in horizontal cylinder, heating the water stored in a water tank. The effects of different aspect ratios are numerically analyzed to inspect the natural convection characteristics in the 2D water tank model. The average and local Nusselt number over the cylinder surface at different aspect ratios and cylinder surface temperature are also discussed.

Numerical study of the low-frequency atomic dynamics in a Lennard-Jones glass

1998 ◽  
Vol 77 (2) ◽  
pp. 473-484 ◽  
Author(s):  
M. Sampoli, P. Benassi, R. Dell'Anna,
Keyword(s):  
Numerical Study ◽  
Low Frequency ◽  
Lennard Jones

Theory of nuclear multifragmentation*(II). Post-transition dynamics

1990 ◽  
Vol 512 (2) ◽  
pp. 345-364
Author(s):  
J LOPEZ ◽  
J RANDRUP
Keyword(s):  
Transition Dynamics ◽  
Nuclear Multifragmentation

Experimental and numerical study of the response of steel sheet Hopkinson specimens

2006 ◽  
Vol 134 ◽  
pp. 541-546 ◽  
Author(s):  
P. Verleysen ◽  
J. Degrieck
Keyword(s):  
Steel Sheet ◽  
Numerical Study

Numerical simulation of the tree higro-thermal response in forest fire environment

2020 ◽  
pp. 57-65
Author(s):  
Eusébio Conceiçã ◽  
João Gomes ◽  
Maria Manuela Lúcio ◽  
Jorge Raposo ◽  
Domingos Xavier Viegas ◽  
...  
Keyword(s):  
Forest Fire ◽  
Numerical Study ◽  
Thermal Response ◽  
View Factor ◽  
Tree Model ◽  
Pine Tree ◽  
Surface Temperatures ◽  
Fire Environment ◽  
Fire Front ◽  
Heat Exchanges

This paper refers to a numerical study of the hypo-thermal behaviour of a pine tree in a forest fire environment. The pine tree thermal response numerical model is based on energy balance integral equations for the tree elements and mass balance integral equation for the water in the tree. The simulation performed considers the heat conduction through the tree elements, heat exchanges by convection between the external tree surfaces and the environment, heat exchanges by radiation between the flame and the external tree surfaces and water heat loss by evaporation from the tree to the environment. The virtual three-dimensional tree model has a height of 7.5 m and is constituted by 8863 cylindrical elements representative of its trunks, branches and leaves. The fire front has 10 m long and a 2 m high. The study was conducted taking into account that the pine tree is located 5, 10 or 15 m from the fire front. For these three analyzed distances, the numerical results obtained regarding to the distribution of the view factors, mean radiant temperature and surface temperatures of the pine tree are presented. As main conclusion, it can be stated that the values of the view factor, MRT and surface temperatures of the pine tree decrease with increasing distance from the pine tree in front of fire.

Sign in / Sign up

Export Citation Format

Share Document