Week 2 - Flow over a Cylinder.
AIM:
To perform the CFD flow analysis on flow over a cylinder with different renolds number.
INTRODUCTION:
To simulate the flow over the cylinder and calculate thestrouhal number for a given problem using ansys
Here we are study the physics of the different renolds number.
we are given that some input datas to the start our simulation.
PART 1:
- Simulate the flow with the steady and unsteady case and calculate the Strouhal Number for Re= 100.
PART 2:
1.Calculate the coefficient of drag and lift over a cylinder by setting the Reynolds number to 10,100,1000,10000 & 100000
2.Discuss the effect of Reynolds number on the coefficient of drag
PREPROCESSING AND SOLVER SETTING:
Let us open the ansys workbench,Now opening the fluent flow
The fluent workflow step is GEOMETRY>MESH>SETUP>SOLUTION>RESULT
Let us Discuss
GEOMETRY>
In the fluent flow right click on the geometry and select the new space claim geometry.
Select the new sketch box and create the rectangular (60*20 m) and cylinder(2 m)
NEW SKETCH PLANE >CIRCLE(2m)>LINE>RECTANGLE(60*20m)
MESH :
- Right click on the mesh and selecting edit option to open the mesh window
- At earlier we finished the GEOMETRY sample
- Click on the generating mesh to automaticaly create the mesh
RIGHT CLICK MESH > GENERATE MESH
- our interest to create the mesh 500 mm and tria method (10098 elements)
RIGHT CLICK MESH > INSERT > METHOD > TRIANGLES
- and using the sizing option to create the 36 devitions for the center cylinder
RIGHT CLICK MESH > INSERT > SIZING > TYPE (number of devitions)
- To use the inflation option to create the first layer thickness height is 5mm and growth rate is 1.2 mm
RIGHT CLICK MESH > INSERT > INFALATION > INFLATION OPTION (first layer thickness)
- Name selection for the geometry inlet ,outlet,symmetry,cylinder wall
SETUP :
Right clickon the setup to click the edit option open the fluent launcher select 3D,double precision and select the number of cores as per system conficuration .
In all conditions we used laminor flow only
PHYSICS>VISCOUS>LAMINOR
A 2 dimensional cylinder was modeled to study the karman vertex street with respect to the renolds number using ansys fluent
The density and viscocity of the flued was manitained 1 kg/m3 and 0.05 kg/ms
The problem was simulated under steady and unstady state
only channge the velocity magnitute for the cylinrytical wall to get the different plots like DRAG CO-EFFICINET,LIFT CO-EFFICIENT,VERTEX AVERAGE AND VELOCITY & PRESSURE CONTOUR DIFFERNTS
FOR USING THE RENOLDS NUMBER FORMULA TO GET THE MAGNITUDE VELOCITY AS PER RN
Velocity magnitude (m/s) for 10 Renolds number = 0.25 m/s
100 Renolds number = 2.5 m/s
1000 Renolds number = 25 m/s
10000 Renolds number = 250 m/s
100000 Renolds number = 2500 m/s
PART 1
Flow simulation for 100 renolds number steady and unsteady conditions
STEADY CONDITION WITH RESPECT TO ITERATION UNSTEADY CONDITION WITH RESPECT TO TIME
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VELOCITY CONTOUR FOR STEADY
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VELOCITY CONTOUR FOR UNSTEADY
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RESIDUAL PLOT FOE STEADY
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RESIDUAL PLOT FOR UNSTEADY
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DRAG PLOT FOR STEADY
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DRAG PLOT FOR UNSTEADY
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LIFT PLOT FOR STEADY
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LIFT PLOT FOR UNSTEADY
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VERTEX AVERAGE FOR STEADY
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VERTEX AVERAGE PLOT FOR UNSTEADY
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STROUHAL NUMBER
PART 2
THE VELOCITY,RESIDUAL,DRAG,LIFT,VELOCITY VECTOR AND VERTEX AVERAGE FOR STEADY STATE CONDITION TO 500 ITERATION
VELOCITY CONOUR COMPARISON
Renolds number increse the cylinder flow also incresed
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RENOLDS NUMBER 10
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RENOLDS NUMBERE 100
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RENOLDS NUMBER 1000
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RENOLDS NUMBER 10000
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RENOLDS NUMBER 100000
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SCALE RESIDUAL COMPARISON
ALMOST ALL THE RENOLDS NUMBER AFTER THE 100 TH ITERATION IT WILL BE CONVERGEN
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RENOLDS NUMBER 10
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RENOLDS NUMBER 100
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RENOLDS NUMBER 1000
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RENOLDS NUMBER 10000
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RENOLDS NUMBER 100000
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DRAG COEFFICIENT PLOT COMPARISON
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RENOLDS NUMBER 10
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RENOLDS NUMBER 100
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RENOLDS NUMBER 1000
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RENOLDS NUMBER 10000
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RENOLDS NUMBER 100000
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LIFT COEFFICIENT COMPARISON
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RENOLDS NUMBER 10
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RENOLDS NUMBER 100
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RENOLDS NUMBER 1000
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RENOLDS NUMBER 10000
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RENOLDS NUMBER 100000
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VERTEX AVERAGE COMPARISON
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RENOLDS NUMBER 10
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RENOLDS NUMBER 100
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RENOLDS NUMBER 1000
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RENOLDS NUMBER 10000
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RENOLDS NUMBER 100000
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VELOCITY VECTOR
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RENOLDS NUMBER 10 |
RENOLDS NUMBER 100
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RENOLDS NUMBER 1000
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RENOLDS NUMBER 10000
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RENOLDS NUMBER 100000
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CONCLUSION
Finaly we get the all values for the renolds number 10,100,1000,10000,10000. the renolds number increse the flow also incresed
in my knowledge renolds number 1000 is better for flow the cylinder