Contribution to Active and Passive Control of Flow around a Cylinder

This numerical study aims to develop a coupled,
passive and active control strategy of the flow around a cylinder of
diameter D, and Re=4000. The strategy consists to put a cylindrical
rod in front of a deforming cylinder. The quasi- elliptical deformation
of cylinder follow a sinusoidal law in order to reduce the drag force.
To analyze the evolution of unsteady vortices, the Large Eddy
Simulation approach is used in this 2D simulation, carried out using
ANSYS – Fluent. The movement of deformation is reproduced using
an internal subroutine, introduced in the form of a User Defined
Function UDF. Two diameters of the rod were tested for a rod placed
at a distance L = 3 ×d, with an amplitudes of deformation A = 5%, A
= 25% and A = 50% of the cylinder diameter, the frequency of
deformation take the values fd = 1fn, 5fn and 8fn, which fn
represents the naturel vortex shedding frequency. The results show
substantial changes in the flow behavior and for a rod of 6mm (1%
D) with amplitude A = 25%, and with a 2fn frequency, drag
reduction of 60% was recorded.

• M. Tahar Bouzaher

• CFD
• Flow separation
• control
• Boundary layer
• rod
• Cylinder.

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