Resumen
One of the most common systems in engineering problems is the multi-column system in the form of an equilateral-triangular arrangement. This study used three-dimensional numerical simulations to investigate the flow around three cylinders in this arrangement at the super-critical Reynolds number ????=3×106
R
e
=
3
×
10
6
, concentrating on the influence on the spacing ratio (??/??
L
/
D
) among cylinders. The instantaneous vortex structures, Strouhal numbers, fluid force coefficients, and pressure distributions are analyzed thoroughly. The present study demonstrated that fluid dynamics is sensitive to ??/??
L
/
D
, by which five different flow patterns are classified, namely single bluff body flow (??/??=1.1
L
/
D
=
1.1
), deflected gap flow (1.2=??/??=1.4
1.2
=
L
/
D
=
1.4
), anti-phase flow (1.5=??/??=2.3
1.5
=
L
/
D
=
2.3
), in-phase flow (2.5=??/??<3.5
2.5
=
L
/
D
<
3.5
), and co-shedding flow (??/??=3.5
L
/
D
=
3.5
). Critical bounds are identified by significant transitions in the flow structure, discontinuous drop and jump of ????
S
t
, and force coefficients.