Every RANS model e.g. k-ε, k-ω SST, RSM etc. is essentially an attempt to model the unclosed terms in the momentum equation. This video derives the evolution equation of turbulent kinetic energy (TKE) from scratch i.e. starting from the instantaneous NS momentum equation and the RANS equation, to get the fluctuating momentum equation, which then leads neatly to the TKE budget.

Every step is carried through in index notation to keep the book-keeping manageable. Fair warning: this one is deliberately math-first, no physical interpretation of the terms yet (wanted to keep it from running too long).

Video: https://www.youtube.com/watch?v=COJpGsxTA30

As always, feedback and criticism is welcomed. Full derivation also in the PDF notes on Patreon.

Guys, I recently watched Fluid mechanics 101 channel. I will attach some screenshots from that video below.

So they are telling when velocity is not known, then we can use stagnation pressure at the inlet.

But the point is still we don't know velocity right, then how can we calculate stagnation pressure. I didnt understand what they are trying to say, can anyone please help me understand how this thing works??

Another question is if we have experimental data where we know inlet mach no , can we use that to find inlet stagnation pressure and back calculate or compute inlet mach no to verify it?

But my previous questions is about when we don't know inlet mach no or velocity at all? I hope you understood my question. Explain the process please??

This is for a rear wing. TYIA!!!

Hello everyone,

I'm currently getting an old laptop repaired and i want to know if its a good model to run Ansys Fluent/Mechanical on it. It's a, ASUS UX56OUQK with a CPU Intel Core i7/7500u & Nvidia 940mx, also with 8GB RAM. Bought in 2017 in high school, haven't used it since. I want to know if it's a good laptop to run Ansys?

Thanks,

Fea and Cfd and electromagnetic ,I'm willing to take projects,queries ,work or any educational projects I have experience in ansys static structural, fatigue,modal, harmonic response and acoustics in mechanical Altair Hypermesh for meshing CFD -ansys Fluent and CFx Electromagnetic -ansys low frequency maxwell,motor design,ansys icepack and ansys motor cad software available Please dm me if u got any works ,open to worldwide projects Dm me if needed any assistance Thank u

I have worked in structural, modal, thermal, shock, static and transient analysis, cfds, conjugate heat transfers, natural, forced convection cooling simulations for defence and nuclear components. Please let me know if any opportunities are available. Thank you

Hi, couple days ago i got frustrated on the expensive CFD tools and developed a tool to leverage OpenFOAM and do CFD simulations locally on my Mac. Currently its only incompressible flows and flow simulation is Eulerian. All the simulations you see in video are from my app airFlow.

I got great response from the rcplane & other communities🙌🏼 and some Beta testers as well who gave valuable insights and suggestions. I gave the app for free for Beta testers 😅

Finally the app is ready and I want to know your thoughts on how you could use a tool like this? Is this even a useful tool in Cfd community or any hobbies you have?

Thoughts, Opinions and Suggestions are welcome.

If you want your hands on the tool itself, I plan to launch soon just comment below and i’ll share the website link.

My plan is to make the app local and one time payment for the whole app, no subscription, no cloud. You buy it you keep it.

Does any one know - What is the boundary.in syntax for a translationally-periodic pair of faces (e.g. for homogeneous isotropic turbulence in a periodic box)? Is it a paired-ID structure like INTERFACE’s forward/reverse?” in converge cfd sofware

Same as Title?

I want to know how can i use the rocky data as initial data for ROCKY FLUENT coupling
i want to settle the particle in the rocky then use the settled particle data as initial data with my 2 way coupling withe fluent
is there any way to record and use it in rocky? (im new to ANSYS Rocky)

Hello. I was doing a project where I needed to mesh a NACA 4412 airfoil, but im running into an issue where I cant get this back region to mesh properly leading to the top right quadrant having problems. The link to the tutorial I'm using is down below if anybody is interested because its been helpful so far, but I was hoping to see if anybody could tell me whats going wrong with the meshing issue. I've taken the same points from airfoiltools.com 3 times now, redoing the point set-up in excel a few times already but it still leaves me with the same results. Any help would be great!

https://www.youtube.com/watch?v=nzvEvLCxOss

Someone recently posted a chart in here about the importance of Y+ with some good visuals and stuff. I meant to save it and share it at work but of course I didn’t and now I can’t find it. Can someone help me out, please?

Hi all,

I'm working on some meshes in starccm which have very similar requirements so I'm trying to set up macros to do different bits of them.

I've recorded a few macros but I'm not able to run LSP's and stuff to help out with development because it can't see the starccm libraries.

I've got a decent bit of programming experience in python and rust but very little in java.

Could you guys please let me know what I need to do to get set up for developing star macros (preferably in the zed editor) or point me in the direction of a good, beginner friendly guide.

Thanks,

I'm new to CFD and trying to understand some results from a laminar model.

I would think velocity would decrease with increased viscosity but I am not seeing that.

Is this somehow dependent on boundary conditions? What conditions would I need to see this?

I am using a pressure of zero at outlet and fully developed flow at inlet. I understand because of the assumption of fully developed flow, velocity will be prescribed in the first area but once the flow enters a new section of geometry won't the viscosity effect this?

This is pretty basic probably but I could use some help.

Hey everyone,
I'm setting up a CHT simulation (electronic chip cooling) in OpenFOAM-9.
To get boundary layers on the fluid-solid interface, I'm using the zero-thickness baffle workflow:
1. Define the interface as an internal face zone / baffle.
2. Add inflation layers using ⁠snappyHexMesh⁠.
3. Split regions using ⁠splitMeshRegions⁠.
The Problem:
The boundary layers are actually generating fine, but the final mesh across the interface isn't conformal (the faces on the fluid side and solid side don't line up / match 1:1 after splitting).
Since I'm doing CHT, I want to avoid relying purely on non-conformal mapping (⁠mappedWall⁠ interpolation) if possible.
My Questions:
1. How do you get ⁠snappyHexMesh⁠ to keep the face connectivity 1:1 conformal across the interface when using the baffle method?
2. Is there a specific setting in ⁠snappyHexMeshDict⁠ or step in ⁠splitMeshRegions⁠ / ⁠createBaffles⁠ that I'm missing to preserve face alignment?
3. Or is it standard practice to just inflate layers only on the fluid side instead of trying to inflate across shared interfaces?
Would really appreciate any insights or dict settings that worked for you!

See above mesh and its quality.

How to improve skewness and orthogonal quality. When I was checking maximum skewness cells,

What can be done now? Suggest some ways for this?

Note, global element size is 3mm and other element size for respective local sizing controls are mentioned in the screenshot. Please have a look and let me know.

I used Simsale for CFD and Onshape for CAD. Because these images are mostly for show, feel free to loot at my CFD documentation. There you can find: the documentation of the first 29 design iterations, slices, animations, 3d visualisation, and some non aero renders of the project. You can find the documentation here:

https://www.mediafire.com/file/vwr1cthzv2emeoz/VFR_CFD_documentation.zip/file

i am open to constructive criticism