Flow over a cylinder
AIM TRANSIENT FLOW SIMULATION OF FLOW OVER A CYLINDER USING SOLIDWORKS FLOW SIMULATION
INTRODUCTION
IN THIS PROJECT WE ARE GOING TO RUN A SIMULATION OF FLUID FLOW (AIR) OVER A PIPE WITH DIFFERENT VELOCITY OR HAVING DIFFERENT REYNOLDS NUMBER ACC. TO GIVEN DATA.
ABOUT CFD CFD simulation was applied to analyse the dynamic behaviour of stirred systems with different impeller geometries. An offline video processing method was developed to compute mixing time and validate simulation results. The CFD simulation results, and the video processing based mixing times were compared to the naked eye experiment. The developed method is a good way to validate CFD models in laboratory environments by using only a camera and suitable video processing tool. However further research might be necessary to eliminate minor data processing problems, and further simulation studies will be conducted and compared to a wider range of experimental data.
FOR NOW, we are using solidworks flow simulation its helps the visualize the flow on our computer this is much much closer to rael world example if we apply all equation and condition properly.so now we start,
WE KNOW THAT
REYNOLDS NUMBER (Re) = inertia force/viscous force
= rho * V * D /Mu
=(ρ* V*D)/μ
Where
ρ is mass density
V is the velocity of fluid
D diameter of cylinder
μ is dynamic viscosity of flowing fluid
Fluid taken as air
Density of air (rho air) = 1.225 kg/m^3
Kinematic viscosity of air @ 293k = 1.516x10^-5 m^2/s
We are going to assumed the air velocity = 10m/s
Length of computational domain taken as (l) = 0.5m
CALCULATION
DIAMETER OF CYLINDER (D) = 0.04 M
LENGTH OF CYLINDER (L) = 0.05M
Re = rho * V * D /Mu
Re = V D/v ( kinematic viscosity (v) = mu/rho)
CASE 01
BASELINE CASE
Re =VD/v
= 10*0.04/1.516X10^-5
=26385.22
=26385(APPORX)
CASE 02
Increasing value of Reynolds number by 20%
So,
New Re value = 26385 + 26385 *20/100
=31662
Velocity corresponding to new Re value
V = Re*v/D
Putting value,we get
V = 31662*1.516x10^-5/0.04
V = 11.999
V=12
CASE 03
Increasing value of Reynolds number by 40%
So,
New Re value = 26385 + 26385 *40/100
= 26385+10554
=36939
Velocity corresponding to new Re value
V = Re*v/D
Putting value,we get
V = 36939*1.516x10^-5/0.04
V = 13.9999
V=14
CASE 04
Increasing value of Reynolds number by 100%
So,
New Re value = 26385 + 26385 *100/100
= 26385+26385
=52770
Velocity corresponding to new Re value
V = Re*v/D
Putting value,we get
V = 52770*1.516x10^-5/0.04
V = 19.999
V=20
CALCULATION FOR SIMULATION TIME
FLOW THROUGH TIME = COMPUTATIONAL DOMAIN LENGTH / VELOCITY
SIMULATION TIME = 2* FLOW THROUGH TIME
TABLE FOR CALCULATED DATA
|
VELOCITY(M/S) |
REYNOLD’S NO |
FLOW THROUGH TIME (l/V) IN SEC |
SIMULATION TIME IN SEC |
|
|
CASE 01 |
10 |
26385 |
0.0500 |
0.1000 |
|
CASE 02 |
12 |
31662 |
0.0416 |
0.0832 |
|
CASE 03 |
14 |
36939 |
0.0357 |
0.0714 |
|
CASE 04 |
20 |
52770 |
0.0250 |
0.0500 |
PROCEDURE
- MODELING PART OF PIPE IN SOLIDWORKS
Dia of pipe is 0.04 m
Length of pipe is 0.05 m
2.CREATE NEW PROJECT BY USING WIZARD OPTION
3.SELECT THE EXTERNAL FLOW CONDITION
4.SELECT AIR AS FLOWING FLUID
5.WE ARE GOING TO ENTER THE FLOW VELOCITY ( 10 m/s ) IN ONLY X DIRECTION
6. mesh Now we create the mesh . its helps the model to divide into many smaller cube so we can see the flow of fluid very close partical level real world example and also helps us to find the fine contour. So we set the golobal mesh setting to 5 . it means , solidworks going to create very fine mesh in computational domain
FINALLY RUN THE SIMULATION FOR DIFFERENT VELOCITY AND FIND VARIOUS PLOT AS WELL AS ANIMATION OF FLOWING FLUID
RESULT
HERE WE REPRESENT THE FOLLOWING PLOT AND ANIMATION ONE BY ONE
CASE 01 VELOCITY ALONG X AXIS 10 m/s
Cut plot for velocity contour
Animation link for velocity variation
Cut plot for pressure contour
Animation link for pressure variation
EXPLANATION
when air hit the cylinder surface due to the circular cross section of cylinder the air get diverges and that result increase in pressure in the contact area region and decrease in velocity of airon other hand the velocity after the impact or a distance from the cylinder vlocity get normal or uniform.
we see the pressure at the top or bottom side have min. value on other hand velocity is maxmium at that region.
from above observation we see that pressure is inversly proportional to the velocity
CASE 02 VELOCITY ALONG X AXIS 12 m/s
Cut plot for velocity contour
Animation link for velocity variation
Cut plot for pressure contour
Animation link for pressure variation
EXPLANATION
when air hit the cylinder surface due to the circular cross section of cylinder the air get diverges and that result increase in pressure in the contact area region and decrease in velocity of airon other hand the velocity after the impact or a distance from the cylinder vlocity get normal or uniform.
we see the pressure at the top or bottom side have min. value on other hand velocity is maxmium at that region.
from above observation we see that pressure is inversly proportional to the velocity
CASE 03 VELOCITY ALONG X AXIS 14 m/s
Cut plot for velocity contour
Animation link for velocity variation
Cut plot for pressure contour
Animation link for pressure variation
EXPLANATION
when air hit the cylinder surface due to the circular cross section of cylinder the air get diverges and that result increase in pressure in the contact area region and decrease in velocity of airon other hand the velocity after the impact or a distance from the cylinder vlocity get normal or uniform.
we see the pressure at the top or bottom side have min. value on other hand velocity is maxmium at that region.
from above observation we see that pressure is inversly proportional to the velocity
CASE 04 VELOCITY ALONG X AXIS 20 m/s
Cut plot for velocity contour
Animation link for velocity variation
Cut plot for pressure contour
Animation link for pressure variation
EXPLANATION
when air hit the cylinder surface due to the circular cross section of cylinder the air get diverges and that result increase in pressure in the contact area region and decrease in velocity of airon other hand the velocity after the impact or a distance from the cylinder vlocity get normal or uniform.
we see the pressure at the top or bottom side have min. value on other hand velocity is maxmium at that region.
from above observation we see that pressure is inversly proportional to the velocity
CONCLUSION
AS WE INCREASE THE VELOCITY OF AIR WE GET WELL UNIFORM FORM OF SIMULATION AND THE THE FLOW WILL GET UNIFORM IN SHOT RANGE LENGTH.
AFTER IMPACT INCREASE IN VELOCITY LEAD THE DECREASE IN PRESSURE DUE TO IMPACT AT CYLINDER SURFACE