Numerical Simulation of the Flow Past a Pair of Magnetic Obstacles - Selected Topics of Computational and Experimental Fluid Mechanics - page 406

Fig. 7 Stability map of the
flow past a pair of magnetic
obstacles side by side. The
gray strip displays the
transition zone between
steady and time-dependent
flow. Re

Vortex shedding

= 1,000

Steady vortex
pair

D

4 Concluding Remarks

In this work, we have investigated numerically using a Q2D model the flow past a
pair of magnetic obstacles side by side at a fixed Reynolds number, Re

1,000.
We analyzed the coupling of the wakes behind the magnetic obstacles under vortex
shedding conditions for different values of the dimensionless separation distance,
namely, D

=

1, 1.5, 2, and 3. From the numerical velocity field, Lagrangian tra-
jectories were obtained which allow to visualize different flow structures. A strong
coupling was found for D

=

1 where the pair of obstacles act as a large magnetic
obstacle that produces a single wake whose dominant frequency is close to the one
found experimentally (Honji and Haraguchi 1995 ) and almost coincide with that of
the flow past a solid cylinder. A more complex pattern was found for D

=

5 where
an intermediate coupling leads to a bistable regime, characterized by a biased flow
with asymmetric flow structures. Finally, a weaker coupling of the wakes was found
for D

= 1 .

3, where well defined in phase wakes are observed. In general
terms, it can be stated that the flow past a pair of magnetic obstacles side by side
presents similar regimes as those observed in the wakes created by a pair of solid
cylinders.

= 2 and D =

Acknowledgments T his work has been supported by CONACyT, Mexico, under project 131399.
J. Román also acknowledges a grant from CONACyT. The authors are grateful to Saul Piedra for
providing the subroutine for the particle tracking that we present in this article.