Flow over a cylinder
Aim:
Simulate the flow over a cylinder for the conditions shown in the video.
2. Calculate the baseline case Reynolds number.
3. 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.
Solution:
Transient flow
The flow of a fluid is transient or unsteady if its flow parameters (i.e. velocity and pressure) are dependent not only on the position in the coordinate system used to describe the field of flow, but also on time. A distinction is made between three different types of transient flow phenomena.
First we are going to calculate the base line case reynolds number and the formula is given below,
Re = (Density * velocity * Diameter)/Viscosity
based on this formula i have calculated the reynolds number and the calculation are shoen bellow;
at baseline condition
Re = (1.225*10*0.035)/1.81x10^-5
Re = 23687.85
at 20% increase
Re = 23687.85*1.2
Re = 28425.41
and from this we are going to find the velocity
28425.41 = (1.225*V*0.035)/1.81e^-6
V = 11.99 = 12m/s
V = D/T
here D-Computational domine Distance = 0.6
T-Time taken
12 = 0.6/T
T = 0.6/12s
T = 0.05s
and time for analysis = 0.05s, overall time analysis = 0.1s and flow throungh time = 0.01s
at 40% increase
Re = 28425.41*1.4
Re = 33162.99
and from this we are going to find the velocity
33162.99 = (1.225*V*0.035)/1.81e^-6
V = 14m/s
V = D/T
here D-Computational domine Distance = 0.6
T-Time taken
14 = 0.6/T
T = 0.6/14s
T = 0.0428s
and time for analysis = 0.0428s, overall time analysis = 0.0857s and flow throungh time = 0.00857s
at 100% increase
Re = 33162.99 * 2
Re = 47375.7
and from this we are going to find the velocity
47375.7 = (1.225*V*0.035)/1.81e^-6
V = 20m/s
V = D/T
here D-Computational domine Distance = 0.6
T-Time taken
20 = 0.6/T
T = 0.6/20s
T = 0.03s
and time for analysis = 0.03s, overall time analysis = 0.06s and flow throungh time = 0.006s
So from the above calcuation we have calculated Re and corresponding work time is also calculated.
Simulation:
First i have designed the cylinder in solidworks with the assumed dimensions a diameter of 35mm and it is extruded up to 50mm and it is saved as with a name of pipe for further analysis.
Thn select simulation and select wizard and give basic data as given in the video and then after creating the project in input data select computational fluide and give 0.6m and -0.3m in x-axis and set ok, then create a basic mesh and in results create cut plots for pressure and velocity and select the front plane for cut plot and run the calculation after the calculation go to animation and create animation on each of the plots, and a video plot is uploaded in youtube and links are given below.
link 1-Pressure:https://youtu.be/RgPJoP-KoDc
link 2-Velocity:https://youtu.be/9khUY2Jqs0Y
Increase the Reynolds number by a factor of 20%
Then select simulation and select wizard and give basic data as given in the video also here the velocity obtained from the 20% increased Renyolds number and then after creating the project in input data select computational fluide and give 0.6m and -0.3m in x-axis and set ok, then create a basic mesh and in results create cut plots for pressure and velocity and select the front plane for cut plot and run the calculation after the calculation go to animation and create animation on each of the plots, and a video plot is uploaded in youtube and links are given below.
link 1-Pressure:https://youtu.be/ewjwQhV41VA
link 2-Velocity:https://youtu.be/aDDblDaWQSI
Increase the Reynolds number by a factor of 40%
Then select simulation and select wizard and give basic data as given in the video also here the velocity obtained from the 40% increased Renyolds number and then after creating the project in input data select computational fluide and give 0.6m and -0.3m in x-axis and set ok, then create a basic mesh and in results create cut plots for pressure and velocity and select the front plane for cut plot and run the calculation after the calculation go to animation and create animation on each of the plots, and a video plot is uploaded in youtube and links are given below.
link 1-Pressure:https://youtu.be/D_EDiFoH9u0
link 2-Velocity: https://youtu.be/o8XGEbWwbhY
Increase the Reynolds number by a factor of 100%
Then select simulation and select wizard and give basic data as given in the video also here the velocity obtained from the 100% increased Renyolds number and then after creating the project in input data select computational fluide and give 0.6m and -0.3m in x-axis and set ok, then create a basic mesh and in results create cut plots for pressure and velocity and select the front plane for cut plot and run the calculation after the calculation go to animation and create animation on each of the plots, and a video plot is uploaded in youtube and links are given below.
link 1-Pressure:https://youtu.be/QKLmq6jTGV4
link 2-Velocity:https://youtu.be/J3p7m5dSqKU
Result:
Finally i have made the analysis and done flow simulation and solved the problem at all the four the conditons and the variation of the results are shown in the video i made and comapred it in the results.