Abstract:
This thesis investigates the fluid dynamics of co-rotating side-by-side cylinders under
varying gap ratios (g*) and Reynolds numbers (Re) to understand vortex suppression, drag
reduction, and lift coefficient behaviors. Numerical simulations conducted with gap ratios
of 0.5, 1, and 3 at Re = 50 and 100 reveal that increasing the gap spacing reduces vortex
interaction, requiring higher critical rotational speeds for wake instability suppression.
Despite this, low rotational speeds (αcrit > 3.5) effectively stabilized the wake. At Re = 50,
stable anti-phase drag coefficients and in-phase lift forces were observed below αcrit = 3.5,
with negative drag coefficients indicating thrust production. At Re = 100, the vortex street
stabilized at αcrit = 3.5 without secondary instability up to α = 5. The study also identified
the formation of small eddies and a virtual body at critical rotational speeds, impacting
fluid dynamics and vortex suppression. These findings highlight the potential for
optimizing rotational speeds and gap ratios to enhance fluid machinery performance,
reduce energy consumption, and improve aerodynamic efficiency in aerospace,
automotive, and marine engineering. This research extends previous studies, offering new
strategies for fluid flow management and contributing valuable insights to the field of fluid
dynamics.
