A Vortex Penalization Method for Flows With Moving Immersed Obstacles

2011 ◽  
Author(s):  
Georges-Henri Cottet ◽  
Federico Gallizio ◽  
Adrien Magni ◽  
Iraj Mortazavi
Keyword(s):  
Bluff Body ◽  
Vertical Axis ◽  
Vortex Sheet ◽  
Reynolds Numbers ◽  
Immersed Boundary ◽  
Vortex Methods ◽  
Penalization Method ◽  
Slip Boundary ◽  
Penalization Methods ◽  
High Reynolds

The aim of this work is to couple vortex methods with the penalization methods in order to take advantage from both of them. This immersed boundary approach maintains the efficiency of vortex methods for high Reynolds numbers focusing the computational task on the rotational zones and avoids their lack on the no-slip boundary conditions replacing the vortex sheet method by the penalization of obstacles. This method that is very appropriate for bluff-body flows is validated for the flow around a moving vertical axis turbine for two transitional and turbulent Reynolds numbers.

A Vortex Immersed Boundary Method for Bluff Body Flows

2010 ◽  
Author(s):  
Georges-Henri Cottet ◽  
Federico Gallizio ◽  
Adrien Magni ◽  
Iraj Mortazavi
Keyword(s):  
Bluff Body ◽  
Vortex Sheet ◽  
Reynolds Numbers ◽  
Immersed Boundary ◽  
Vortex Methods ◽  
Slip Boundary ◽  
Wide Range ◽  
Penalization Methods ◽  
High Reynolds ◽  
Bluff Body Flows

The aim of this work is to couple vortex methods with the penalization methods in order to take advantage from both of them. This immersed boundary approach maintains the efficiency of vortex methods for high Reynolds numbers focusing the computational task on the rotational zones and avoids their lack on the no-slip boundary conditions replacing the vortex sheet method by the penalization of obstacles. This method that is very appropriate for bluff-body flows is validated for the flow around a circular cylinder on a wide range of Reynolds numbers.

scholarly journals Vortex Penalization Method for Solid-Porous-Fluid Media With Application to Passive Flow Control

2013 ◽  
Author(s):  
Chloé Mimeau ◽  
Iraj Mortazavi ◽  
Georges-Henri Cottet
Keyword(s):  
Flow Control ◽  
Immersed Boundary Method ◽  
Flow Dynamics ◽  
Immersed Boundary ◽  
Vortex Methods ◽  
Penalization Method ◽  
Passive Flow Control ◽  
Passive Flow ◽  
Fluid Media ◽  
Penalization Methods

In this work, a coupling of vortex methods with penalization methods is proposed in order to accurately and easily handle solid-fluid-porous media. This immersed boundary approach indeed maintains the efficiency and the robustness of vortex methods and allows to model the three different media without prescribing any boundary condition. In this paper, we propose an application of this immersed boundary method to passive flow control around a semi-circular cylinder, realized adding a porous sheath on the obstacle surface in order to smooth the flow dynamics.

High Reynolds Number Airfoil Simulations Using the Immersed Boundary Method

2012 ◽  
Author(s):  
James P. Johnson ◽  
Gianluca Iaccarino ◽  
Kuo-Huey Chen ◽  
Bahram Khalighi
Keyword(s):  
Immersed Boundary Method ◽  
High Reynolds Number ◽  
Aerodynamic Force ◽  
Reynolds Numbers ◽  
Computational Approach ◽  
Immersed Boundary ◽  
Pressure Distributions ◽  
Boundary Method ◽  
High Reynolds ◽  
Naca 0012

The Immersed-Boundary Method is coupled to an incompressible-flow RANS solver, based on a two-equation turbulence model, to perform unsteady numerical simulations of airflow past the NACA-0012 airfoil for several angles of attack and Reynolds numbers of 5.0×105 and 1.8×106. Qualitative characterizations of the flow in the vicinity of the airfoil are obtained to show the need for locally refined grids to capture the thin boundary layers close to the airfoil leading edges. Quantitative analysis of aerodynamic force coefficients and wall pressure distributions are also reported and compared to experimental results and those from body-fitted grid simulations using the same solver to assess the accuracy and limitations of this approach. The Immersed-Boundary simulations compared well to the experimental and body-fitted results up to the occurrence of separation. After that point, neither computational approach provided satisfactory solutions.

FLIGHT SIMULATIONS OF A TWO-DIMENSIONAL FLAPPING WING BY THE IB-LBM

2013 ◽  
Vol 25 (01) ◽  
pp. 1340020 ◽  
Author(s):  
YUSUKE KIMURA ◽  
KOSUKE SUZUKI ◽  
TAKAJI INAMURO
Keyword(s):  
Rotational Motion ◽  
Lattice Boltzmann ◽  
Translational Motion ◽  
Reynolds Numbers ◽  
Flapping Wings ◽  
Immersed Boundary ◽  
High Reynolds ◽  
The Stability ◽  
Boltzmann Method ◽  
Flight Simulations

The stability of flight by flapping wings is investigated by using the immersed boundary-lattice Boltzmann method (IB-LBM). First, the rotational motion with an initial small disturbance is computed, and it is found that the rotational motion is unstable for high Reynolds numbers. Second, we show simple ways to control the rotational and translational motion by bending or flapping the tip of the wing.

Scaling laws for drag of a compliant body in an incompressible viscous flow

2008 ◽  
Vol 607 ◽  
pp. 387-400 ◽  
Author(s):  
LUODING ZHU
Keyword(s):  
Viscous Flow ◽  
Scaling Laws ◽  
Scaling Law ◽  
Soap Film ◽  
Power Laws ◽  
Reynolds Numbers ◽  
Flow Speed ◽  
Immersed Boundary ◽  
Incompressible Viscous Flow ◽  
High Reynolds

Motivated by an important discovery on the drag scaling law (the 4/3 power law) of a flexible fibre in a flowing soap film by Alben et al. (Nature vol. 420, 2002, p.479) at high Reynolds numbers (2000<Re<40000), we investigate drag scaling laws at moderate Re for a compliant fibre tethered at the midpoint and submerged in an incompressible viscous flow using the immersed boundary (IB) method. Our work shows that the scaling of drag with respect to oncoming flow speed varies with Re, and the exponents of the power laws decrease monotonically from approximately 2 towards 4/3 as Re increases from 10 to 800.

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