VOF Simulations of Gas Bubbles Motion in a Reciprocally Stirred Flow

2010 ◽  
Vol 44-47 ◽  
pp. 2494-2498
Author(s):  
Hong Liu ◽  
Mao Zhao Xie ◽  
Hong Chao Yin ◽  
De Qing Wang
Keyword(s):  
Surface Tension ◽  
Flow Field ◽  
Numerical Simulations ◽  
Liquid Flow ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Navier Stokes Equations ◽  
Mesh Method ◽  
Gas Liquid Flow

This paper reports progress in the numerical simulations of movement and the coalescence of two neighbor bubbles (leading and trailing bubble) in a reciprocally stirred liquid flow field. The full Navier-Stokes equations are solved by the volume-of fluid (VOF) method for tracking the interface between the bubble and the liquid flow. A dynamic mesh method was used to predict the gas-liquid flow in a two-dimensional foaming tank. Results indicate that the motion and merge behavior of the bubbles is dominantly influenced by the initial locations and the sizes of the bubbles as well as by the surface tension, while the reciprocating effect is insignificant.

scholarly journals Unsteady Reversed Stagnation-Point Flow over a Flat Plate

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Vai Kuong Sin ◽  
Chon Kit Chio
Keyword(s):  
Laminar Flow ◽  
Flow Field ◽  
Asymptotic Solution ◽  
Stagnation Point ◽  
Stokes Equations ◽  
Stagnation Point Flow ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Total Flow ◽  
Navier Stokes Equations

This paper investigates the nature of the development of two-dimensional laminar flow of an incompressible fluid at the reversed stagnation-point. Proudman and Johnson (1962) first studied the flow and obtained an asymptotic solution by neglecting the viscous terms. Robins and Howarth (1972) stated that this is not true in neglecting the viscous terms within the total flow field. Viscous terms in this analysis are now included, and a similarity solution of two-dimensional reversed stagnation-point flow is investigated by solving the full Navier-Stokes equations.

Aerodynamics of a two-dimensional flapping wing hovering in proximity of ground

2019 ◽  
Vol 233 (12) ◽  
pp. 4316-4332 ◽  
Author(s):  
Yunlong Zheng ◽  
Qiulin Qu ◽  
Peiqing Liu ◽  
Yunpeng Qin ◽  
Ramesh K Agarwal
Keyword(s):  
Flow Field ◽  
Stokes Equations ◽  
Aerodynamic Force ◽  
Ground Effect ◽  
Flapping Wing ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Navier Stokes Equations ◽  
Lift Mechanism ◽  
The Difference

The difference in aerodynamic forces of a two-dimensional flapping wing hovering in unbounded flow field and ground effect is studied. The unsteady laminar Navier–Stokes equations are solved by the finite volume method to simulate the flow field around the wing. In the unbounded flow field, the correspondence between the aerodynamic force, pressure distribution on wing, and typical vortex structures is established, and then the high-lift mechanism of the flapping wing is further explained. In the ground effect, based on the lift variation, the dimensionless height H/ C ( H is the height of the wing above ground and C is the chord length of the wing) can be divided into transition and ground effect regimes. In the transition regime ( H/ C > 2.5), the lift decreases with the decreasing height, and the ground indirectly impacts the vortices near wing by changing the shed vortices in space. In the ground effect regime ( H/ C < 2.5), the lift increases with the decreasing height, and the ground directly impacts the vortices near the wing.

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