Flow simulation of air flowing over cylinder for different Reynolds number.

Problem statement:

1. Run a baseline simulation and then calculate the Reynolds number.
2. Run a baseline simulation and then calculate the Reynolds number. Then 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.
4. Explain your observations.

Procedure:

step 1:

• First we need to run a Baseline simulation where we do not considered the Reynolds number and depending on the inlet velocity we calculated the constant value as follows.
• First we begin with the creation of the part i.e. cylinder, using the 'Extrude boss/base' command. Gometrical parameters of the cylinder are:diameter D = 0.05m and length L = 0.1m.and inlet velocity in x-dir as 10m/s.
• Then select flow simulation and then go to wizard option. put all input parameters and initial conditions.i.e. name to the project, Select the units system and here the flow is over the cylinder hence, the type of analysis is External.
• with Vin = 10m/s and Computational domain length decided as 1m our flow through time is 1sec and the end time as 2x of flow through time i.e. 2sec.

step 2:

After running the analysis we get the result. As we're interested in the Pressure and Velocity(x) and the animations for both. We create two cut plots one each for Velocity(x) and for Pressure.

step 3:

For animation, Click on Animation option and insert a new animation. In the animation window click on wizard, select scenerio as we're interested in the flow as well. Now delete the plot that has been entered by the system and right click in the line just below that of the link created by the wizard that will be for Velocity. Now run the animation.

step 4:

now by clculating reynolds number by baseline simulation condition, we calculated reynolds number and increase it by 20%,40% and 100%

we got values for velocities equal to 12m/s,14ms and 20m/s for 20%,40% and 100% respectively.

conclusion:

• As per observation of pressure and velocity plots for different reynolds number, pressure and velocity changed significantly over different reynolds number as inlet velocity increases.
• As inlet velocity increases then velocity plot showing significant changes i.e from 10m/s to 20m/s.
• hence flow simulation with time based analysis showing correct results for different reynolds number.

drive link:https://drive.google.com/open?id=1zM5JLK9iPljZOIasWHqbgEltyxXXjNCr