Flow over a cylinder

Aim:

1) Run a baseline simulation and then calculate the Reynolds number.

2) Increase the Reynolds number by a factor of 20%, 40%, and 100%, then run the transient flow simulation.

3) Create animations for pressure-velocity for all the three Reynolds number.

Parameters & dimensions:

Cylinder diameter = 100 mm

Length = 200 mm

Base Velocity= 10 m/s

density of air= 1.225 kg/m3\">m3m3

dynamic viscosity= 1.81*10-5\">10−510-5 (at 15° c)

Calculation:

Re = rho*V*D/mu

D = cylinder diameter

mu = dynamic viscosity

rho = density

Solution:

at 10m/s

Reynold number=67680

Case 1: Increased Reynold\'s number by 20% (By increasing inlet velocity)

Velocity Simulation:

Animation:

Pressure Simulation:

Animation:

Case 2: Increased Reynold\'s number by 40% (By increasing inlet velocity)

Velocity Simulation:

Animation:

Pressure Simulation:

Animation:

Case 3: Increased Reynold\'s number by 100% (By increasing inlet velocity)

Velocity Simulation:

Animation:

Pressure Simulation:

Animation:

Conclusion:

1) As the Velocity & Reynold\'s number increase, time required to become velocity profile & pressure steady decreases. At same time, the velocity plot at 20% and 40% exhibit slight unsteady plot whereas at 100% the flow is steady.

2) There is only minor variations in the pressure plots in all cases.