1. Effect of Flow over a Cylinder MAE 5130 Viscous Flow Final Project
By Shreya Raje

2. Introduction
Formation of wake
Vortex Shedding

3. Objective
To find the effect of flow over a cylinder in terms of following parameters:
Pressure
Velocity
Vorticity

4. Approach
For this a two dimensional circular cylinder is drawn along with the direction of flow field perpendicular to its axis in gambit.
Cylinder
Flow Field
Inlet Velocity
Pressure Outlet
Periodic
Wall

5. Meshing

6. Parameters for Calculations for Laminar Flow
An unsteady flow condition was selected to compute the parameters.
Consider Flow Field to be Water
Velocity (U) m/s
Density (ρ) kg/cubic m
Kinematic Viscosity (µ) kg/m-s
Cylinder Diameter (D) 0.25m
Area of each Cylinder (A) 0.5 sq m
Renolds number (Re) = (UxDxρ)/µ =2.5x105

7. Parameters for Calculations for Laminar Flow
To see the effect of vortex shedding the frequency is calculated with Strouhal Number as 0.2
Strouhal Number, St= fxD/U
f= hz
Cycle time,t=1/f=4.976sec
time step size=4.976/25 =0.199sec

8. Contour of Static Pressure for Laminar Flow

9. Contour of Velocity Magnitude For Laminar Flow

10. Contours of Vorticity Magnitude For laminar Flow

11. Path lines with Vorticity Magnitude for Laminar
Flow

12. Parameters for Calculations for Turbulent Flow
An unsteady flow condition was selected to compute the parameters.
Consider Flow Field to be Water
Velocity (U) 2.5 m/s
Density (ρ) kg/cubic m
Kinematic Viscosity (µ) kg/m-s
Cylinder Diameter (D) 0.25m
Area of each Cylinder (A) 0.5 sq m
Renolds number (Re) = (UxDxρ)/µ = 1.244x106

13. Parameters for Calculations for Turbulent Flow
To see the effect of vortex shedding the frequency is calculated with Strouhal Number as 0.2
Strouhal Number, St = fxD/U
f = 1hz
Cycle time,t=1/f=1sec
Time Step Size=1/25=0.04sec

14. Contour of Static Pressure for Turbulent Flow

15. Contour of Velocity Magnitude For Turbulent Flow

16. Contours of Vorticity Magnitude For Turbulent Flow

17. Path lines with Vorticity Magnitude for Turbulent Flow

18. Results And Conclusion
Sr No
Parameter
Flow
Obtained
Values
Theoretical 1
Angle
Laminar
Approx 80o
82o
Turbulent
Approx
130o
120o 2
Coeffient of Drag
0.8166
1.2
0.4614
0.3