Flow over a cylinder

                                                                     PROJECT REPORT

                                                              FLOW OVER A CYCLINDER

OBJECTIVE: 

To perform the external pipe flow simulation by using wizard option, and increase the reynolds number by a factor of 20%, 40%, and 100% and then run the transient flow simulation.

GEOMETRIC PARAMETERS :

• Diameter = 0.02 m.
• length = 0.05 m.
• Fluid = air.
• rho = 1.225 kg/m³
• mu = 1.81 × 10^-5kg/(m. s)

CALCULATION: 

For the base line simulation the velocity is 10 m/s.

                                                           Re = rho*U_inlet*D/mu

                                                                                                           where, D = cylinder diameter

                                                                                                                      mu = dynamic viscosity

                                                                                                                      rho = density

 For case 1 : v1 = 10m/s   Flow Time 1 = 0.02s. 

                    Re = (1.225 * 10 * 0.02) / (1.81 × 10^-5)

                    Re = 13535.9116

For case 2 : By increasing the reynolds number by 20%, Re = 16243.09392

                   V2 = 12 m/s.  Flow Time 2 = 0.03s.

For case 3 : By increasing the reynolds number by 40%, Re = 18950.27624

                   V3 = 14 m/s.  Flow Time 3 = 0.025s.

For case 4 : By increasing the reynolds number by 100%, Re = 27071.8232

                   V4 = 20 m/s.   Flow Time 4 = 0.018s

PROCEDURE :

FIRST, Model the cylinder as per the given dimension below and save it.

SECOND, Calculate the baseline reynolds number by using the given parameters using the Reynolds Number formula,

                      Re = rho*U_inlet*D/mu,

                                                                  where rho=density,D=diameter, U_inlet=10m/s, mu=viscosity.

                    Take baseline reynolds number Re=13535.91.

THIRD, Using this calculate the three reynolds number by using 20%, 40%,100% of baseline reynolds number.

FOURTH, Create a wizard and set the requires conditions like air medium, time dependent, external flow and velocity.

FIFTH, Measure the computation domain and calculate the flow time and end time.

SIXTH, Insert the cut plot at the middle of cylinder and show velocity and pressure plot for all the three reynolds number.

SEVENTH, Create an animation for both velocity and pressure plot for all the three values.

RESULTS : 

Case 1 : At 20% of baseline reynolds number:

i} Velocity Plot                                                             ii} Presssure Plot

iii} Presssure Animation                                                   iv} Velocity Animation

https://youtu.be/P_B8csmUsos                                               https://youtu.be/GcUnf2cvg1s

Case 2 : At 40% of baseline reynolds number:

i} Velocity Plot                                                                ii} Presssure Plot

iii} Velocity Animation                                                   iv} Presssure Animation

      https://youtu.be/NQy3YABsh-U                                         https://youtu.be/iurnOOLRkQE

Case 3 : At 100% of baseline reynolds number:

i} Velocity Plot                                                             ii} Presssure Plot

iii} Velocity Animation                                                   iv} Presssure Animation

     https://youtu.be/MLwQ2Ksaj5c                                          https://youtu.be/YVW44IIdEYI

CONCLUSION:

1. With increase in reynolds number, the velocity and pressure flow increased.

2. The velocity at the front side of cylinder is very high when compared to other sides of cylinder.

3. There is slight difference in pressure in all the three reynolds number.