What is The Step in Solving CFD
Basically, there’s 3 step in solving CFD.
1. Preprocessing
2. Solver
3. Post Processing
Preprocessing step includes:
- The geometry (physical bounds) of the problem is defined (Problem statement information about flow)
- Mathematical Model IBVP = PDE + IC + BC
- The volume occupied by the fluid is divided into discrete cells (the mesh). The mesh may be uniform or non uniform.
- The physical modeling is defined – for example, the equations of motions + enthalpy + radiation + species conservation
- Boundary conditions are defined. This involves specifying the fluid behaviour and properties at the boundaries of the problem. For transient problems, the initial conditions are also defined.
Solver step is doing simulation and the equations are solved iteratively as a steady-state or transient.
Finally a postprocessor is used for the analysis and visualization of the resulting solution. and Verification model validation / adjustment
Where CFD can be Applied?
Every Fluid flow problems can be solved using CFD, such as phenomena in our daily life:
• meteorological phenomena (rain, wind, hurricanes, floods, fire
• environmental hazards (air pollution, transport of contaminan
• heating, ventilation and air conditioning of buildings, cars etc
• combustion in automobile engines and other propulsion system
• interaction of various objects with the surrounding air/water
• complex flows in furnaces, heat exchangers, chemical reactors
• processes in human body (blood flow, breathing, drinking . . .
• and so on and so forth
Can CFD replaced The Experimental Need?
CFD Can’t fully replaced experimental need, but CFD offer cheaper cost than experimental. Besides. CFD give insight flow pattern that are difficult, expensive or impossible to study using traditional (experimental) techniques. CFD still need experimental result because CFD developed from experimental Result.
Here’s the different between Experimental and Simulation
As a note, the results of a CFD simulation are never 100% reliable because
• the input data may involve too much guessing or imprecision
• the mathematical model of the problem at hand may be inadequate
• the accuracy of the results is limited by the available computing power
2 comments:
Very nice intro. Thanks for that. I am a chemical engg graduate. But have been mostly into technology sales. My current field is two/three phase separation and I am interested to learn CFD in order to be able to do CFD analysis of separators on oil and gas platform that require debottlenecking. How do you think I should start and what I should learn. I have seen your other post about the 11 lecture series. It is quite tough to go back to the TPI basics and refresh PDE, tensors, vectors!
Hi Sudarshan.
Transport Phenomena is tough (I think so). You don't need to learn that again, at least if you only want to get practical result in CFD Analysis. It's different when you need Deeper result, as when we're in university.
I suggest you start learning your CFD Software, (gambit first to draw your continuum, and then FLUENT to do analysis). If you don't have it, now there's free software called OPENFOAM. You can googling it.
If your assignment wasn't in Fluent (as I am), then you need a little "work hard" to finally understand how to handle this program. You better check out Cfdonline.com to search more help, as I still busy to add post. :)
Good Luck
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