Flow over a cylinder

FLOW OVER A CYLINDER

AIM
To simulate flow over a cylinder under different reynolds number and simulation time and analyse the results.

CALCULATIONS

The base line calculations

viscocity= 1.84*10^-5 Pa.s
density=1.225 Kg/m^3
velocity=10m/s
diameter=0.004m
therefore
Re=(V*D*density)/viscosity=26630.43

Re and velocity at 20%increase = 31956.516 and 12m/s
Re and velocity at 40%increase = 37282.602 and 14m/s
Re and velocity at 100%increase= 53260.86 and 20m/s

computational domain length = 0.36m

Flow through time for 12m/s = 0.36/12= 0.03s
Flow through time for 14m/s = 0.36/14= 0.0257s
Flow through time for 20m/s = 0.36/20= 0.018s

End time at 12m/s = 0.03*2 =0.06s
End time at 14m/s = 0.0257*2=0.0514s
End time at 20m/s = 0.018*2 =0.036s

PLOT

RE @ 20%
Velocity

Pressure

RE @ 40%
Velocity

Pressure

RE @ 100%
Velocity

Pressure

OBSERVATIONS
The main observation that can be derived is that the velocity increases with the reynold's number. Also the simuation time decreases with the rise in velocity.

The variations for pressure and velocity are almost same. The high pressure at front of the cylinder is due to the obstruction to the wind(inlet velocity).