Tandem Analysis Effects on Bluff Bodies Aerodynamics

Flow over the bluff body is considered an
interesting topic that has long piqued the curiosity of
aerodynamic experts because of its unusual flow
behavior. Moreover, bluff bodies used in tandem have
several technical applications, including high tower
buildings, railways trains, industrial chimneys, and road
vehicles, in addition to several other applications.
Nevertheless, the non-streamed bodies with sharp
leading ends are subjected to very high-pressure drag.
Recognizing the flow through these bodies contributed to
the design optimization and management of the field
using passive or active techniques. Hence, the primary
goal of this research is to quantitatively explain the flow
field and effect of shielding of different square plates

positioned concentrically as front bodies square flat-
faced upstream sharp leading edges in addition to the

rounded back rear body. Furthermore, this study
considered a 3D analysis of the fluid flow behavior near
the rear body alone, considering various geometrical
combinations of gap ratios and width. Also, this study
involves three Reynolds numbers depending on the rear
body width, which is in the range of 1-1.8 ×105 were

considered. Results were obtained using ANSYS-
FLUENT (19.1) software depending on Computational-
Fluid-Dynamic (CFD) applied to the K-Ɛ turbulence

model to solve the general equations and, therefore, test
the prepared models. The flow properties were
simulated, involving the components of flow stream

velocity, pressure distribution, and the Pressure-
Coefficient (Cp) of the front-rear body and near the rear

body alone combinations. Results showed that the most
effective combination is achieved when the g/b2 value
equals 0.5 b1/b2 value equals 0.75.This
decrease is because of the impact of the front body's
shielding, which causes separation streamlining on the
front body's reattachment close to the shoulder of the
rear body. Moreover, the instantaneous streamline
velocity contour, as well as drag coefficient distributions,
were computed. The obtained numerical results showed
a good agreement with the experimental outcomes.