1. COMPUTATIONAL INVESTIGATION OF
UNSTEADY FLOWS ACROSS BLUFF BODIES AT
HIGH REYNOLDS NUMBERS
By Project Guide
Mr. Surendra
Rajesh Kancheti Bogadi
(0928024) Assistant Professor
Dept. of Aeronautical Engg.

2. OBJECTIVE
• Flow over Bluff Body.
• Flow at different angle of attacks.
• Flow over the bodies when they are kept in tandem configuration and in
v-configuration .
• To view the vortex shedding behind the wake of the body.
• Computational work is being carried out using FLUENT for coefficient of
pressures, and to see the effect of flow turbulence on the wake bodies.

3. PROCEDURE
• The model here is the circular cross-section bluff
body composed using GAMBIT with structured
mesh.
• For each angle of attach we need to determine
the following coefficients
Lift
Drag
Pressure

4. PROCEDURE
• The values determined needs to be validated
with the pre defined data and the best results
are plotted .
• Observe the vortices behind the body to
analyze on how it is going to effect the other
body which would be in the wake region.

5. CONFIGURATIONS
• This is an example photograph of circular
cross-section bluff body

6. PLAN OF
WORK
2D structured grid
Single cylinder with different
diameter ‘s
Three cylinders in tandem
position with different
diameter’s
Three cylinders in v-
configuration with different
diameter’s

7.  Solution Settings:
 CFD code: Fluent 6.3.26
• Finite Volume Method based
Navier-Stokes Solver
 Solver: Pressure Based
 Viscous Model: K-epsilon
• Standard K-epsilon model
 Discretization schemes:
• Time: 2ndorder implicit
• Momentum: 2ndorder upwind
• Pressure-Velocity Coupling: SIMPLE
 Boundary conditions:
 Default Interior: Interior
 Fluid : Fluid
 Inlet: velocity-inlet
 Outlet: Pressure outlet
 Cylinder: wall
 Lower & upper extent : Wall

8.  Inlet conditions:
 Velocity inlet
 Specification method = k and Omega
 Velocity magnitude = 4.39m/s
 Turbulent kinetic energy(m2/s2) = 0.0145
 Specific dissipation rate(1/s) = 0.0569
 Velocity magnitude = 4.39m/s
 Turbulent kinetic energy(m2/s2) = 0.0145
 Specific dissipation rate(1/s) = 0.0569
 Transient Solution:
 Time step size: 1.701 second
 Total time steps: 800
 Run time: 9 hours
 Hardware: Intel(R)core(TM)i3 processors, 3 GB RAM, 2.39 GHz,
Windows 7 64-bit operating system

9. Boundary conditions created for single cylinder
for both Re=1.5 x 103 & 5.3 x 107

10. Cp vs Angle for single cylinder

11. The vortex shedding is visualized for single cylinder with
respect to time by means of the Velocity Vorticity
Magnitude Contour for Re = 5.2 x 107 at 00 AOA

13. Domain created for three cylinder
in Tandem configuration

14. Grid created for three cylinder in
Tandem configuration

15. Cp vs θ for three cylinders in
Tandem at 0 of AOA
0
Re=1.5 x 103 Re=5.2 x 107
1.5
1.0
1.0
0.5
0.5
Angle (deg) Angle (deg)
0.0 0.0
0 50 100 150 200 250 300 350 0 50 100 150 200 250 300 350
-0.5
Cp -0.5
Cp
-1.0
-1.0
C1 -1.5
-1.5 C2
-2.0
c1
C3 c2
-2.0 -2.5 c3

16. The vortex shedding is visualized for Tandem with respect to
time by means of the Velocity Vorticity Magnitude Contour for
Re = 5.2 x 107 at 00 AOA
t=680sec t=1190sec

18. Cp vs θ for three cylinders in
Tandem at 300 of AOA
Re=1.5 x 103 Re=5.2 x 107
1.5
1.0
1.0
0.5
0.5
Angle (deg) Angle (deg)
0.0
0 50 100 150 200 250 300 350 0.0
0 50 100 150 200 250 300 350
-0.5 -0.5
Cp Cp
-1.0
-1.0
c1 -1.5
-1.5 c2 c1
c3 -2.0 c2
-2.0
c3
-2.5

19. The vortex shedding is visualized for Tandem with respect to
time by means of the Velocity Vorticity Magnitude Contour for
Re = 5.2 x 107 at 300 AOA
t=680sec t=1190sec

21. Cp vs θ for three cylinders in
Tandem at 450 of AOA
Re=1.5 x 103 Re=5.2 x 107
1.5
1.0
1.0
0.5 Angle (deg)
0.5
Angle (deg) 0.0
0 50 100 150 200 250 300 350
0.0
0 50 100 150 200 250 300 350 -0.5
-0.5
Cp Cp
-1.0
-1.0 -1.5
-1.5 c1 -2.0 c1
c2 c2
-2.0 -2.5 c3
c3
-2.5 -3.0

22. The vortex shedding is visualized for Tandem with respect to
time by means of the Velocity Vorticity Magnitude Contour for
Re = 5.2 x 107 at 450 AOA
t=680sec t=1190sec

24. Cp vs θ for three cylinders in
Tandem at 90 of AOA
0
Re=1.5 x 103 Re=5.2 x 107
1.5
1.0 1
Angle (deg)
0.5
Angle (deg) 0
0.0 0 50 100 150 200 250 300 350
0 50 100 150 200 250 300 350
-0.5 -1
Cp -1.0 Cp
-1.5 -2
-2.0 c1
c1 -3 c2
-2.5
c2 c3
-3.0 c3 -4

25. The vortex shedding is visualized for Tandem with respect to
time by means of the Velocity Vorticity Magnitude Contour for
Re = 5.2 x 107 at 900 AOA t=1190se
t=680sec c

27. Domain created for three cylinder
in V-configuration position

28. Grid created for three cylinder in
V-configuration

29. Cp vs θ for three cylinders in V-confiuration at 00
of AOA
Re=1.5 x 103
1.5
1.0
0.5
0.0 Angle (deg)
0 50 100 150 200 250 300 350
-0.5
Cp
-1.0
-1.5 c1
c2
-2.0 c3
-2.5
Re=5.2 x 107
1.5
1.0
0.5
Angle (deg)
0.0
0 50 100 150 200 250 300 350
-0.5
Cp -1.0
-1.5
-2.0
-2.5 c1
c2
-3.0 c3

30. The vortex shedding is visualized for V-configuration with
respect to time by means of the Velocity Vorticity Magnitude
Contour for Re = 5.2 x 107 at 00 AOA
t=680sec t=1190sec

32. Cp vs θ for three cylinders in V-confiuration at 300 of
AOA
Re=1.5 x 103 Re=5.2 x 107
1.5 1.5
1.0
1.0
Angle (deg)
0.5
0.5
Angle (deg) 0.0
0 50 100 15 20 250 300 350
0.0 -0.5
0 50 100 150 200 250 300 350 0 0
-0.5 -1.0
Cp Cp
-1.0 -1.5
-2.0 c1
-1.5 C1 c2
C2 -2.5 c3
-2.0 -3.0
C3
-2.5
-3.5

33. The vortex shedding is visualized for V-configuration with
respect to time by means of the Velocity Vorticity Magnitude
Contour for Re = 5.2 x 107 at 300 AOA
t=680sec t=1190sec

35. Cp vs θ for three cylinders in V-confiuration at 450 of
AOA
Re=5.2 x 107 Re=5.2 x 107
1.5 1.5
1.0 1.0
0.5 Angle (deg)
0.5
Angle (deg)
0.0
0.0 0 50 100 150 200 250 300 350
0 50 100 150 200 250 300 350 -0.5
-0.5
Cp Cp
-1.0
-1.0
-1.5
c1
c2
-1.5
C1 -2.0 c3
C2 -2.5
-2.0
C3
-3.0
-2.5

36. The vortex shedding is visualized for V-configuration with
respect to time by means of the Velocity Vorticity Magnitude
Contour for Re = 5.2 x 107 at 450 AOA
t=680sec t=1190sec

38. Cp vs θ for three cylinders in V-confiuration at 700 of
AOA
Re=5.2 x 107 Re=5.2 x 107
1.5
1.5
1.0
1.0
0.5
0.5 Angle
Angle (deg)
0.0
0.0
(deg)
0 50 100 150 200 250 300 350 0 50 100 150 200 250 300 350
-0.5
-0.5
Cp
-1.0 Cp-1.0
-1.5
-1.5
C1 -2.0
-2.0 C2 c1
C3 -2.5 c2
-2.5
-3.0
c3

39. The vortex shedding is visualized for V-configuration with
respect to time by means of the Velocity Vorticity Magnitude
Contour for Re = 5.2 x 107 at 700 AOA
t=680sec t=1190sec

41. Cp vs θ for three cylinders in V-confiuration at 900 of
AOA
Re=5.2 x 107 Re=5.2 x 107
1.5 1.5
1.0 1.0
0.5
0.5
Angle (deg)
Angle (deg) 0.0
0.0 0 50 100 150 200 250 300 350
0 50 100 150 200 250 300 350 -0.5
-0.5
Cp Cp
-1.0
-1.0
-1.5
-1.5 -2.0
C1 -2.5
-2.0
C2 c1
C3 -3.0 c2
-2.5 c3

42. The vortex shedding is visualized for V-configuration with
respect to time by means of the Velocity Vorticity Magnitude
Contour for Re = 5.2 x 107 at 900 AOA
t=680sec t=1190sec

44. CONCLUSIONS
• The flows around the circular cylinders with
different configuration were investigated. The
results obtained are in good agreement with
previous literature results.
• It has been observed that V-configuration is
better suitable for situations where high
pressures are expected on the wake bodies and
tandem configuration is suitable for situating
where pressure expected not to change
considerably .

45. • In the three cylinders in v-configuration flow
effect is more on the upstream bodies this is
visualized by capturing the velocity vorticity
magnitude contours with respect to the time.
• Frequency is not possible to calculate or
capture in the wake of the bodies.
• In Tandem configuration at 90° AOA the three
cylinders will become as a individual bodies.
• in V-configuration at 90° AOA the first
cylinder acts as a individual body.

46. SCOPE OF FUTURE WORK
It is worth to carry out further studies for better
understanding some of them are listed below;
Can be extended to 3-D
Different orientation can be adopted.
Different shapes can be used.
Experimental work can be done.

47. THANK YOU