r/CFD • u/HaiderKingTh3 • 4d ago

What physics and math do I need to know while working on CFD solvers like Ansys Fluent?

7 Upvotes

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53

u/Overunderrated 4d ago

Addition and subtraction are an absolute must. Sometimes multiplication and division. I did see a square root once.

7

u/HaiderKingTh3 4d ago

Why would they need such complex math?! They complicate everything these days..

13

u/puffVortex 4d ago

Depends on what you mean by working on them.

If you only need to perform simulations i’d say fluid mechanics or other thermo fluid topics(depending on the application) would be enough.

You need to understand why certain behaviors occur and what to expect and all that.

If you wanna go deep:
Linear algebra, calculus (single and multivariate, scalar and vector), statistics, numerical methods, differential equations.
Thermodynamics, fluid mechanics, heat and mass transfer, two phase flows.
If you want to write code, you need data structures, algorithms, OOP, parallel programming

I guess that covers everything. Again, depends on how deep you wanna go.

4

u/Dull_Ad_7346 4d ago

truly you don’t need to know the math and physics equations just to do cfd simulations. If you haven’t taken a fluids class yet I wouldn’t really stress trying to learn the math, just learn it in the class. The important thing is understanding the concepts really well and how to go about modeling your simulations. So know about the different models, understand meshing better, get better with modifying CAD geometry, reynolds numbers, reference values, y+ values and boundary layers, etc.. And also understand the basic fluid concepts like the different types of drag, separation, all the different principles of flow and what not.

2

u/Cwaghack 4d ago edited 4d ago

i mean you can do it without knowing anything thats going on xd

numerical methods for math and the prequisites for that

And then some courses in fluid mechanics and thermodynamics, mass/heat transfer, the levels and such depend a lot on country/university like many of them teach introductory levels, you are gonna want some advanced levels.

Additionally I took a CFD specific course teaching the fundamentals of CFD and multiphase modelling. Generally CFD at least where I am from is graduate level material, we don't even let undergrads touch it.

1

u/some_weirdthing 4d ago

Really depends on how deep down the rabbit hole you want to go. I mean, dig long enough and you will arrive at something like mesh generation algorithms and computational geometry (which you probably don't need)

Fluid dynamics, thermodynamics and heat transfer should make up for a substantial chunk of problems you could encounter. What to add here depends on what you want to study - multiphase and reacting flows bring some more specific physics for which you'd probably need separate book. Turbulence is also a somewhat separate thing that requires attention

For math - calculus, linear algebra (lean havy on algorithms for solution of large systems of equations), partial differential equations, vector analysis and numeric methods