CFD ANALYSIS OF FLOW AROUND A CYLINDER (RESULTS)

Here are few results compiled from the Cylinder simulation. I have chosen the following Reynolds numbers for the study: 30, 200, 10000, 1*10^6. 

Reynolds Number 30:

Figure No.1: Flow Visualization 
At a low Reynolds number of 30, the vortex shedding has not begun and so the force Coefficient of lift could not be calculated, as shedding is reason for the lift to exist.

Reynolds Number 200:


Figure No. 2: Force Coefficient & Strouhal number

For a Reynolds number of 200, the vortex shedding takes place and thus producing lift and drag. The force Coefficients are calculated in the above plot as Clrms = 0.3357 Cdmean = 1.2201 St = 0.19.

Reynolds Number 3500:

Figure No. 3: Force Coefficient & Strouhal number
The force coefficients were calculated to be the following: Clrms = 1.014 Cdmean = 0.18 St = 0.19.

Reynoldes Number 10000:
For Reynolds number of 10^4, a DES based turbulence model was employed and the force coefficients were calculated. 


        Figure No. 4: Force Coefficient & Flow Visualization
Cdmean = 1.0264 Clrms = 0.4652 St = 0.1852.

Reynolds Number 1000000:
The simulation was performed on two grids of one, a coarse mesh and second a refined grid. 
Figure No.5: Coarse grid Clrms

Although the value of the plot is not clear, the Clrms value for a coarse grid had an error of 20%. And then a refined grid was utilized.

                             Figure No.6: Force Coefficients

The force coefficient values are as follows: Cdmean = 0.4054 Clrms = 0.059 St = 0.29.


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