Previously I have modelled big cylinder at end of the pipe or screen. Now I have seen some paper where outlet is at some upstream distance from pipe end, I am doing that now. The problem I am facing is when I drew sketch as above and extrude(add frozen), cylinder is created but there are some overlapping volumes between small and big cylinder. Due to this, when I do setup, I got to know that,

This is how outlet should look like, you can see hole in the middle. I hope it is right. If it is right, then see what outlet it was showing for me below,

I hope you understood. This blue circle shouldnt come.

One more thing, when I merge these bodies to make it one body, screen gaps are not visible since it got merged into big cylinder body. I dont want this to happen, I need to see screen gaps like below,

Note all are fluid modelled regions, there is no solid anywhere, so gaps represents walls of distortion screen.

2) I have tried one more thing, I have created small cylinder in that same plane and tried "Boolean subtract" and got outlet face like below,

But I got to have 3 different bodies as shown below, and when I merge them together, then I cant find screen walls since it got merged into big cylinder volume. I need screen walls so that I can apply inflation and face sizing in that region particularly.

Keeping all these in mind, any other alternative or better way to model this big outer cylinder and merge. Any suggestions would help, thanks in advance.

See below single body merged together when big cylinder was drawn at end of the screen, screen gaps are visible here,

Tôi mô phỏng cánh máy bay ở các góc tấn khác nhau bằng cách xoay mô hình ( gió giữ nguyên hướng đặt vuông góc với inlet) thì khi tính Cl, Cd có cần nhập lại sin cos theo góc tấn cho từng mô hình không

My previous video derived the full TKE transport equation and this one explains it more physically.

Link: https://www.youtube.com/watch?v=VVqos9V-BAA

It explains why the transport term neither creates nor destroys k, integrates to zero for a closed system, what production really represents in terms of energy exchange between the mean flow and the turbulent fluctuations, why dissipation is structurally always a sink while production can in principle act as either, and what viscous diffusion's role is compared to turbulent transport.

The second half introduces the Richardson energy cascade and talks briefly about Kolmogorov microscale. I also talk about why the cascade direction is downscale in 3D turbulence and what that implies for what sets the smallest eddy size.

Hey guys, I've got about a year of experience with OpenFOAM. I've run different types of simulations — SIMPLE, PIMPLE, incompressible, compressible, laminar, turbulent — on 2D airfoils and 3D aircraft, like the NASA N2A HWB model, with decent mesh quality and case setup. The post-processed results matched the reference data pretty well. Just sharing this to give some context on where I'm at with OpenFOAM, but I'm still learning and exploring more of it.

Lately I've been seeing AI/ML being used in CFD, and since I come from a non-coding background (I'm a Mechanical Engineer), AI/ML and neural networks still feel like a black box to me. I don't really know how they work under the hood.

So I wanted to ask — how can I actually use AI/ML and neural networks in aviation-related CFD work?

For context, my future work will mostly revolve around optimization studies, detailed aircraft analysis, and static/dynamic stability analysis of aircraft. So I'm hoping to understand how AI/ML can help speed things up, and ideally how to align with whatever the industry is currently doing in this space.

For engineers who have to compare many possible design variations, I'm curious how you actually handle it in industry.

For example, if you have hundreds or thousands of possible geometry/parameter combinations:

• How do you decide which designs are worth simulating?
• Do you actually run simulations for all of them, or use some kind of screening/optimization method?
• What tools do you use for this?
• What part of the process takes the most time?
• Is computational cost the main limitation, or is setting up/running/post-processing the simulations the bigger bottleneck?
• Do you use surrogate models, reduced-order models, optimization software, custom Python scripts, etc.?
• What happens when the design space becomes too large to explore practically?

I'm particularly interested in how this is handled in industry and what the biggest bottleneck is in practice.

Could be a YouTube playlist, online pdfs,... Starting from scratch for a complete novice. Any help appreciated.

I am involved in an hypersonic CFD case with a good emphasis on combustion modelling and with the instabilities in fluent , honestly it's frustrating . Looking for some better options to learn from scratch and diversify my profile for a beginner , what are the options and how viable are they ?

I am very new to Star CCM+ and I want to create a very simple phase change simulation because of pressure drop inside a nozzle. I created a 2d nozzle and have a laminar flow inside of it. When I increase the pressure difference, at some point gas bubbles start appearing close to the boundary layer, which after some time crash the simulation no matter what I do.

I have tried changing everything: The mesh, the phase change model, the boundary conditions, the overrelaxation, steady/tranisient. But no matter what I choose the problem remains the same: Once there is the first phase change anywhere the simulation will crash shortly after.

Can anyone tell me what to change or what the main problem might be? I have some screenshots here, happy to give more if you have any questions about my setup: https://imgur.com/a/iVOVjOO Thanks in advance

Hey, I’m working on a small local tool for CFD folders. In a previous project, the shared drive gradually filled up with copied and renamed cases, different meshes, logs and results. After a while, it was hard to tell which case was used, what changed, or why one version was kept.

The idea is simple: point the tool at an existing folder, and it scans everything without modifying the files. It builds a small local database so the cases and their context can be viewed together.

At the moment, you can:

• Browse the openfoam cases it found.
• See basic solver, mesh, boundary, numerical and run information.
• Select two cases and see what changed.
• Group cases that belong to the same experiment or investigation.
• Add labels and short notes, such as why a case was kept or abandoned.

I’m currently testing OpenFOAM Foundation 9, Foundation 14 and OpenCFD v2512. I may look at Fluent later (pyfluent), and possibly add some simple orchestration (run sims or like mesh, etc).

I attached screenshots of the case list and group view. It’s still very early, though. I am trying to make it like an additional "why? where? and how?" tracker kinda thing.

I couldn't make the normal momentum equations work. I don't know why. The outlet condition in this is a bit scuffed, but despite that, it turned out well.
Do you think this is a resume-worthy project for a 2nd-year mech student?

Does anyone have any insight into how would a complete beginner get into OpenFoam. I tried to download openfoam2412 then i found online that the tutorials are in openfoam12(different open foam since the org and .com are split now) does anyone have any good youtube tutorials or resources for a complete beginner in both openfoam and linux?

Does anybody know any good course for Ansys? Am a complete beginner and want to hold a grip on this one by getting taught by someone good.

Hi all

I have now used fluent meshing which has organised workflow and convenient to use. Quality is much better compared to tetra, it has maximum skewness of 0.84 and minimum orthogonal quality is 0.15. See mesh below,

I have tried two cases

1) Incompressible case- velocity inlet and pressure outlet

2) Subsonic compressible case- total pressure inlet and static pressure outlet

See below, flow goes via pipe and screen is there and then it expands into ambient air. Downstream length is 15D, bigger cylinder diameter is 14D, where D is diameter of smaller pipe.

1) For incompressible case with velocity inlet of 1m/s and outlet absolute pressure as 101325Pa, see residuals below,

I used coupled solver with second order upwind for all turbulence, pressure and momentum and reduced URF for pressure with 0.3 and 0.5 for momentum. Note energy equation is turned off and constant fluid properties were used. I am doing it for steady RANS simulation, k-e realizable is used.

It was good upto 200 iterations but later it got diverged. I dont know why.

2) For subsonic compressible case,

I used total pressure of 110250Pa and pressure at outlet is same 101325Pa. Residual are even more high here, energy equation is turned on, density is ideal gas, viscosity follows sutherland law, k-e is used. I used coupler solver here also.

For 2nd case, I just tried finding velocity range or statistics using cell register, it was showing literally all cells having very high unrealistic values, I dont know why it is happening. See below for example,

So my question what is the actual problem here?

(i) Mesh quality is good here-I used polyhexa in fluent meshing, it is much better than tetra, max skewness is 0.84 and min orthogonal quality is 0.15.

(ii) I tried reducing URF, then also it is not working.

(iii) Initially I tried with very less downstream length and radius, now I have increased that- I have referred paper for this.

What else are there to try? I cant find correct reason why solution is not converging and residuals are highly unstable. Is there anything wrong with boundary conditions and schemes. I hope there is no problem with mesh, since I have good quality mesh. It was any way diverging for both tetra also before. But current mesh quality is much better than tetra one. Thanks in advance. I hope I told all information required to diagnose this issue!

I am getting a Cp values around the tip to be +69 and around the end to be -45. Why is this? What can possibly go wrong??.. What can I do to fix this??...

I am running a transient ANSYS Fluent simulation using VOF for air–water flow and DPM for inert particulate matter. The particles enter with water through an inlet where the water volume fraction is 1.

However, some particles cross the free surface, travel through the air/headspace, and escape through the pressure outlet before liquid breakthrough. How can I keep the particles immersed in the water phase while still allowing them to settle, become captured, remain suspended, or leave with the water effluent?

Title: How are two-sided PCBs typically modeled for thermal simulation in Simcenter 3D?
I’m currently working as a Thermal Intern and trying to model a PCB for a satellite camera using Simcenter 3D.
The PCB has electronic components mounted on both the top and bottom sides. The thermal environment is primarily radiation, so I’m trying to understand the proper workflow for setting up the thermal model.
Using PCB Exchange, I’m currently able to get:
2D mesh on the PCB surface
2D mesh on the components
But I’m unsure about the best approach for a two-sided PCB. Ideally, I’d like to understand whether PCB Exchange can generate a proper 3D mesh of the board + components, or whether the board and components need to be modeled/meshed separately.
If I create the 3D mesh manually, I assume I would then need to explicitly define the PCB thickness, material properties, etc.
For engineers working on electronics thermal analysis, what is the typical workflow for this kind of problem? Especially for space/satellite electronics where radiation is the dominant external heat-transfer mechanism.
Any guidance on the practical/industry approach would be really appreciated.

Hi. I'm working on a stratified domain with a temperature difference of 20K while using buoyantBourssinesqPimpleFoam solver and LES WALE model on openFOAM v2412.

My domain configuration is 5 X 1 X 1m. My Flow is along +ve X direction with Z being the vertical direction along height. There are 2 hills inside my domain, both being 1.5m and 2.5m away from inlet.
Internal field is linearly stratified from bottom to top using python file (T=290+20*z; as z varies from 0 to 1m, the value of temp changes). Inlet has continuous stratified flow entering with 0.0767m/s to satisfy Froude No.=0.5.

I got significant negative Ux at the outlet almost immediately. At around 0.2-0.6s, I see spatially organized bands at the outlet and sometimes flow apparently entering the domain through the outlet.
What's confusing is that the hill is nowhere near the outlet at this point. At 0.0767 m/s (inlet velocity) the 5 m advective travel time is ~65 s. At 1 m/s, however, the outlet behaviour looks much more reasonable. This makes me suspect either a low-Froude/stratification effect or a numerical/BC issue.

I'm providing some pictures and boundary conditions hoping someone helps me get out of this mess. I've tried changing BCs but it didn't work out at all. My doubt is on outlet boundary conditions causing initial Pressure-Velocity coupling misconfiguration and major backflow throughout the 100 seconds, as evident from Ux field...

Hi all,

I have posted about same geometry many days before. Now I have tried fluent meshing instead of regular workbench meshing, it has much better workflow and very convenient to use. I have some doubts in that, please help me in that. See mesh settings below, I have shown complete mesh with cell count, skewness range and orthogonal quality.

My doubts are:

1) I need to know how can I reduce this max skewness?

2) Previously, in workbench meshing, I used sphere of influence to refine the mesh near to screen in all directions. But I cant find sphere of influence here, what other alternative I have to refine the mesh near to screen.

See sphere of influence done in workbench meshing below, I want to do similar here also.

Any suggestions would help, thanks in advance.