Flow over a cylinder
Aim:
To stimulate the velocity and pressure on a cyclinder where the fluid having different reynolds number is flowing over the cyclinder.
Introduction:
Computational fluid dynamics (CFD) is a branch of fluid mechanics that uses numerical analysis and data sructures to analyze and solve problems that involve fluid flows. Computers are used to perform the calculations required to simulate the free-stream flow of the fluid, and the interaction of the fluid (liquids and gases) with surfaces defined by boundary conditions.CFD is applied to a wide range of research and engineering problems in many fields of study and industries, including aerodynamics and aerospace analysis, weather simulation, natural science and environmental engineering, industrial system design and analysis, biological engineering, fluid flows and heat transfer, and engine and combustion analysis.
In this project we using the Solidworks software to design and to perform the flow simulation.
Problem datas:
Let us assume the below datas to solve the problem.
Diameter of the cyclinder = 0.04m
Length of the cyclinder = 0.05 m
Lets the flow across the cyclinder be Air
density of air = 1.225 kg/m^3 (predefined values)
viscosity of air = 1.81*10^-5 kg/ms (predefined values)
Length of the domain be 0.6 m
Flow through time is the time required by the fluid to flow from inlet to outlet.
Therefore, flow through time = Length of the domain/ Velocity
= 0.6/0.8
= 0.75 seconds.
In the problem statement it is given that the end time should be twice the flow through time,
end time = 2*flow through time
=2*0.75
=1.5 seconds.
Calculation of reynolds number,
baseline case Reynolds number.
`Re = (rho*V*D)/mu`
- Re = reynolds number
- V = inlet velocity
- D = cylinder diameter
- mu = dynamic viscosity
- rho = density
`Re = (1.225*0.8*0.04)/ (1.81*10^-5)`
Re = 2165.75 ~ 2166
Below cutplot represent the velocity change during the flow of fluid over the cyclinder
Below cutplot represent the pressure change during the flow of fluid over the cyclinder
If reynolds number value is incresed to 20%:
Increased reynolds number = 2598.9
Then the velociy for the above reynolds number be = 0.96 m/s
Below cutplot represent the velocity change during the flow of fluid over the cyclinder
Below cutplot represent the pressure change during the flow of fluid over the cyclinder
If reynolds number value is incresed to 40%:
Increased reynolds number = 3032.05
Then the velociy for the above reynolds number be = 1.12 m/s
Below cutplot represent the velocity change during the flow of fluid over the cyclinder
Below cutplot represent the pressure change during the flow of fluid over the cyclinder
If reynolds number value is incresed to 100%:
Increased reynolds number = 4331.5
Then the velociy for the above reynolds number be = 1.6 m/s
Below cutplot represent the velocity change during the flow of fluid over the cyclinder
Below cutplot represent the pressure change during the flow of fluid over the cyclinder
Setup explanation:
- Cyclinder 3d model is created.
- New flow simulation project is created.
- Make sure that the external flow is created.
- Inlet velcoity is given as input data.
- Cutplots for velocity, pressure is created.
- Run the simulation
- Then load the cutplots .
- Created animations for the velocity, pressure changes.
Conclusion:
Thus the required simulations are obtained for various reynolds number.