I've been trying to use Ansys fluent (Student version) but everytime I start the program I get this warning saying that there's no license available. Workbench runs fine. I've also got similar problems when I open any of the other Ansys programs (as shown in the second image).

I've already checked that the program has access through the firewall to both private and public networks and I've tried uninstalling and installing again but the problem persists.

I also checked a similar post in this same subreddit and saw people mentioning the number of nodes or processes as a problem with the student license. Following the advice there, I tried running Fluent with 1, 2, 3 and 4 processes having the same issue each time.

I hope someone will be able to help me figure this out.

Hey everyone!

I'm a 31-year-old mechanical engineer with several years of experience in Oil & Gas (Project Engineer), Tool Installation (Team Lead), and currently BIM (Technical Expert / Mechanical Piping Modeler).

My dream has always been to work in automotive or aerospace engineering, especially in design and aerodynamics. However, career opportunities led me elsewhere, as these fields are almost nonexistent in my country due to the lack of R&D.

Now that I've graduated, I'm considering pursuing a Master's in Computational Mechanical Design in Europe to transition into CFD, aerodynamics, or mechanical design.

My question is: Is this a realistic career move at 31, with no professional experience in CFD or design? Would my previous engineering experience be valuable, or would I essentially be starting from scratch?

Thanks for your time!

In the era full of low job availablity(especially for freshers in CFD),,, what makes you love CFD, or be in this subs... You can directly learn some other skills and have good initial salary.. Right???

I have some conceptual doubts, which I didn't get clear explicit answer from sources in net,

1) What is difference between node values on/off in looking the contours? I observed values are relatively higher when I turned off node values. Please tell me cases or situations where we should turn on or turn off node values with reason. How does this affect in viewing contour, finding range of parameter in some selected surface or cell zones.

2) I have some trivial doubt about operating pressure. The point is- In momentum equation , it contains pressure gradient not absolute pressure, so fluent choose some reference pressure i.e operating pressure. So instead of solving with very large pressure, it works with smaller numbers since deltaP remains the same with the concept of operating pressure. Density is calculated using absolute pressure only.
This concept is same for both incompressible and compressible flow right, but why do they say for compressible flow you have to set operating pressure as zero, I didnt understand what is the reason for this? Can anyone explain elaborately please? Thanks in advance.

this 2d cfd sim uses upwind differencing schemes and uses ndarray and rayon to ensure its fast so im confused as to what to do with the tiny dt caused by cfl conditions and heres the tiny project
https://github.com/busysofa15/2026_projects/blob/534578f75d4ce511587d2f012a219a9b95a588e0/rust_projects/compressible_fluid_sim/src/main.rs
and the dt condition is around lines 86 to 99
any help would be appreciated 👍️

I wanted to see the temperature contour of Heat exchanger but it's been more than 1 hour still it's loading any solution?

Hi all, I am a new student researcher starting my journey in OpenFOAM. I inherited a project from a former PhD student who wrote a customized solver based on icoReactingMultiRegionInterFOAM from ESI version v2306, and I have only been simulating cases with that specific solver. My PI is now asking me to model nucleation within a vapor plume in the current case, and I found that OpenFOAM Foundation v14 has the exact solver I need (homogeneousNucleation.H). What are the best next steps to include the solver in my new cases? Should I also learn to write a custom solver? If so, how do I include the OpenFOAM Foundation solver in ESI?

Hello everyone,

I've been trying to get this benchmark propeller (Potsdam Propeller Test Case) analysis to work but I can't mesh it with SHM. Inflation layers are not good enough and I can't get the desired y+ values for the case.

I also need some kind of surface refinement or wrapper. The geometries I use have self intersections that are easily handled in StarCCM+ but with snappy, checkMesh finds errors due to these bad STL elements.

What is your go to method for meshing thin lifting surfaces like wings, propellers etc.? I am honestly losing my mind trying to get it to work. I really need some help.

Thank you all in advance.

I'm signed up to take the Programming CFD training w/ Greenshields next month. I haven't done any OpenFOAM trainings with them before.

Anyone here completed the training? If not Programming CFD, one of the other ones? From what I've read they're really good. I'm mostly interested in the training material and book I can take back with me.

As the title suggests, I am noticing a change in wall shear stress, and thus wall HTC, along my object. I am benchmarking the heat transfer on a 2d ellipse and am currently conducting a grid sensitivity on the ellipse edge sizing. Upon halving the edge elemnt size (refinement ratio 2), the leading edge now shows higher and lower regions in the form of "bands" (see below). Any help on this is appreciated.

Model information:

• Turbulent (k-omega)
• Transient (100s with 10s timestep)
• Mesh consists of a sweep method (2d approximation), edge sizing (grid sensitivity focus), and inflation (first layer thickness for y+ = 1)
  
• Residulas RMS < 10^-4, MAX < 10^-3

Hi everyone,

Video #8 of the (free) turbulence course I'm creating is now up on YouTube. This one is very much applied where I take a PIV time series, generated from the cover video, of a turbulent jet and compute flow statistics in MATLAB, explaining each step.

It covers the mean and fluctuating velocity profiles, going further into Reynolds stresses (normal and shear), and then longitudinal and transverse two-point correlation functions and second-order structure functions relative to the centreline.

The scripts are deliberately short, so they're meant as a template for anyone who wants to run the same statistics on their own PIV, hot-wire or numerical simulations data.

Link: https://www.youtube.com/watch?v=Z7Q0k4P1V8k

Notes (and scripts) are available on Patreon (free membership option available). Happy to answer questions about the analysis.

So i am a Strucutral engineering PhD with very little experience in CFD. But I was able to use Claude to build a model and run an analysis for my new PCbuild for various fan configurations. Its crazy it could use OPENFoam to run the analysis and make all these videos.
Attached is the actual parameters it used for the analysis
https://drive.google.com/file/d/1FIkQLUMF1yODekwAvPoyq672vEh6ikCU/view?usp=sharing

Hi everyone,

I'm working on a full 3D fluid-structure interaction (FSI) simulation involving multiple bodies attached to a common rotating shaft. Each body is approximately 2 m long, with a very small gap (around 5 cm) between adjacent bodies. The main challenge is handling the large rotational motion of the structure while maintaining good mesh quality, particularly in the narrow gaps between the bodies.

I've been using multiple overset mesh regions in OpenFOAM, but this approach introduces several challenges, including mesh interpolation, computational cost, and difficulties handling closely spaced overset regions. Setting up and maintaining this configuration in OpenFOAM is also quite complicated.

I'm wondering whether anyone has experience with similar configurations or could suggest alternative approaches.

A few options I'm considering:

• Immersed boundary methods that avoid continuous mesh deformation.
• Dynamic mesh deformation with adaptive remeshing.
• Other CFD/FSI frameworks or software that might handle this configuration more efficiently.

My main objective is to accurately capture the aerodynamic interactions between the bodies and their coupled structural motion, including potentially large rotations, without sacrificing mesh quality or making the computational cost prohibitively expensive. Has anyone dealt with a similar problem? Would you recommend a different meshing strategy, solver, or even alternative software to OpenFOAM for this type of simulation?

I'd really appreciate any suggestions, experiences, or references to similar studies.

Thanks!

Random Sunday Project

I am simulating an enclosed parking garage in Autodesk CFD.

- Garage area: approximately 1,974 m2
- Mechanical exhaust: 4,200 m3/h
- Natural make-up air through wall openings and the garage door
- Clean incoming air: scalar = 0
- Required CO emission: 247 g/h
- Target: below 100 ppm at 1.7 m height

I use a scalar transport model where scalar 0 represents clean air and scalar 1 represents pure CO.

Initially, I modelled the entire driving area as one large Internal Fan region with a flow rate of 0.02 m3/s. I calculated the source scalar using:

Scalar = CO mass flow / (air density x source volume flow)

This resulted in a source scalar of approximately 0.0027. However, the scalar at the exhaust was approximately 0.0012, which seems too high.

I am now considering several long rectangular source regions along the driving lanes. Each source would be 0.6 m wide, and the CO emission would be distributed according to the source lengths.

What is the correct way to model a known CO emission rate of 247 g/h in Autodesk CFD?

- Should I use Internal Fans, volumetric sources, or another source type?
- Can the scalar be calculated from CO mass flow divided by air density and source volume flow?
- How can I ensure that the model injects exactly 247 g/h?
- How should I verify this with a mass balance at the mechanical exhaust?
- Does anyone have experience in these kinds of simulations?

Any advice on modelling contaminant sources in Autodesk CFD would be appreciated.

Hi! I’m trying to run a CFD simulation of airflow over a bicycle helmet in ANSYS fluent and i’m not sure where i’m going wrong? The quality of my cells is fine I think and I used y+sqrt(74)*re^(-13/14) for my y_1 value using last ratio on my walls. I think the issue is with the y1 value though?

my results are SO wrong getting 0 velocity anywhere in the system (set inlet to 10m/s) pressure is whack and getting 0 y+ values for my entire system. setting my residuals to converge at 1e-03 which i know is a bit high? also using standard k epsilon turbulence model

This is my first time trying a proper 3D model, usually for class we’ve just extruded the cross section. Maybe I should go back to that?

I’m really a beginner at this so any help at all would be so appreciated thank you!!

I posted this post here a while ago:
https://www.reddit.com/r/CFD/s/ynCa0b4g8i

Since then, I’ve been trying to improve my mesh, I switched from a tetrahedron to a poly hex-core and also started using fluent meshing. (Attached is my current mesh). Currently it has orthogonal minimum of 0.3 and skewness maximum of 0.48.

But despite my efforts on trying to improve my mesh. The residuals still almost look the same from before. Could it be a setting issue? Or is my mesh still really that bad?

My current configuration has energy equation on, viscous laminar model, pressure based, steady time, gravity off. Mass flow inlet at 0.06kg and 293K with pressure outlet 0Pa gauge and 293K. Heat flux at 20000 is applied at the bottom outer face.

The solver settings are currently on coupled, least square based gradient, second order on pressure, second order upwind on momentum, and second order upwind on energy. I tried to change momentum to first order a while ago, and that actually made it go down by a lot, but I heard that it’s less accurate so I switched back to second order upwind.

My control settings are currently on default which are pressure and momentum at 0.5, density and body forces at 1, and energy at 0.75. I tried lowering this values before, but nothing changed so I just reverted them back to the original.

I tried to see if there is a mass imbalance and got. Mass flow rate inlet at 0.06 and outlet at -0.06004121. So I don’t think there’s much of at imbalance.

I also tried comparing my results from a paper I’m basing this baseline geometry to and got 139.18Pa for the area weighted average of my inlet compared to his 139.59. And 311.9588K for my Area weighted average of my heated wall compared to his 314K(I also need help possibly bringing this closer). I think it’s also good to note that from improving my mesh, I did get a better inlet pressure, because before I was getting 134Pa.

Any advice would be greatly appreciated 😊.

Hi, I'm quite new to CFD and I'm having major problems with meshing. I'm studying the drag coefficient on an elliptical and tangent ogive nose cone and I'm using a 2D axisymmetric geometry. From what I read on literature it's important to have y+ close to 1 on the first layer near the wall, because with this setup the model (k-omega SST in this case) doesn't need to use wall functions. I don't understand from what criteria I need to subdivide the edges or what element size to use to have an accettable mesh; then in ansys meshing if I use a general mesh element size to small (and I don't know what is too small for it) the meshing process get's stuck at 5% when converting triangular elements to quads. Is there any literature, videos or piece of knowledge I should read or watch to really understand meshing? I feel like I'm walking in the dark. If needed I will upload the domain I was trying to mesh.

Hello everyone.

I’m trying to replicate some experimental analysis with Ansys Fluent. Particularly I’m trying to simulate a Wells turbine on different airflow conditions (same RPM, different inlet velocities).
The goal is to plot torque and pressure coefficients over time/flow coefficient.
I’m getting very bad torque values, about 50% of the experimental results (more on that below).

Here’s the setup:

I created a CAD with same exact geometry features of the tested turbine.

I imported it into Ansys, considered just the duct in which the air flows (just like the OWC simulator in the real test). Divided the domain into 3 zones, two stationary and 1 MRF. (I considered no tip gap to avoid strange behavior there, since 1mm of gap it could be hard to simulate). Also, only simulated 1/6 of the turbine, a single blade passage (6 blades in tot)

Meshed and open fluent.

The solver is Ansys Fluent, I set up the air conditions (viscosity and density). I set up the MRF rotational speed and inlet velocity on 9m/s (i want to get one condition right before analyzing more intel speed values). Used k omega.

I initialized and run 500/1000 iterations.

Data obtained:

CFD (Torque on a single blade):

Pressure: 0.016280575 Nm
Viscous: 0.0025203426 Nm
Total: 0.018800917 Nm

Experimental results at 65Hz and 9m/s of inlet speed vel:

0.206 Nm, which divided by 6 give me: 0.0343 Nm

That's about 54% of the exp data

Thanks everyone:)

I’ve just got my first potential customer, and I’m willing to compromise on the money for some brand visibility. I wonder generally what’s the pay?

They have a small electronics box and want to run the analysis on it.

I’m an employed fresher engineer with a BSc in Mech engineering if this is relevant

Hi

Fire safety of battery energy storage systems, and I would love advice on which software to invest in learning.

What I want to simulate:

Thermal runaway in prismatic LFP cells and how it propagates cell → module → rack → neighbouring racks

I am interested in getting the heat release rate (HRR) and total heat release (THR) of a burning rack.

Effect of rack spacing and of insulation layers (between cells, modules and racks) on propagation

Later: a full battery room (~10 MWh, 40 racks) thermal runaway simulations

Options I'm considering: Ansys Fluent, STAR-CCM+, FDS (with PyroSim), OpenFOAM.

Which GUI tool would you pick to do runaway + venting + combustion + HRR in one workflow?

Thanks a lot.

Hi everyone,

I’m a 3rd-year aerospace engineering undergrad, and I’m an international student. I have to choose my specialization right now, and I’m really stuck. I’d appreciate some honest advice.

My situation:

• I can do well in both CFD and structures/materials.
• I genuinely love CFD more.
• But I keep hearing that as an international, CFD/aerospace jobs in the US are very tough because of ITAR/export control and visa sponsorship issues.
• My goal is to go directly into a funded PhD in the USA after my bachelor’s.
• At my university, there is no aerodynamics/CFD professor. The only relevant professor is in structures/materials.
• The lecturer who supervises thesis students is very helpful, much better than the other teachers, but he only has a master’s degree.
• I’m worried that if i work with both the professor and have papers in both areas, it might make me look unfocused to PhD admissions committees.

My main questions:

1. Should I formally specialize in structures/materials because that’s where I can get proper supervision, while keeping CFD as a side skill?
2. Or should I still try to pursue CFD even though there’s no CFD professor to guide me?
3. For US PhD admissions, does formal specialization matter, or do research output and letters of recommendation matter more?
4. How should I present papers in both areas on my CV/SOP so I don’t look unfocused?
5. Any advice for an international aiming for a direct US PhD in aerospace/mechanical engineering?

I’d really appreciate advice from people who’ve been through US PhD admissions, especially internationals in aerospace or mechanical engineering.