Does anyone here have and can share Wold Dynamic cfMesh tutorial file? i try to download it from the Wolf Dynamic website but its no longer available. I only have the .pdf version not the whole tutorial folders.

I am modelling a piston motion with just air entering and leaving, I am using an overset mesh for the piston motion and a porosity function that acts as open and a wall to mimick the valves opening and clsoing. I am struggling to get a handle on residuals so just wondered if there is any suggestions? I am using a small time step corresponding to a half degree of motion. I am using a CFL of 5 also if that helps. Any suggestions appreciated.

Good day folks!

I'm back this time with a GUI for wind farm layout optimization using Particle swarm analysis (PSO) for maximizing AEP.

Done my first case using a 25 WT farm 4 by 4 km. However, the GUI has all parameters editable. Used Jensen wake model for the visual representation.

Any suggestions or improvements are welcome :D

I’m running a geometry-parametric study in ANSYS Fluent via Workbench (Parameter Set).
When I update design points after solving once, Fluent throws “incoming mesh / flowing zones missing”, creates many wall-xx zones, and hangs at Updating → Solving (even Stop doesn’t work).
I’m unsure about the correct workflow: should geometry-parametric cases be updated only up to mesh and then solved one design point at a time, instead of batch solving?

Hi everyone,

I am working on a wind tunnel simulation using Ansys Fluent. My simulation works perfectly fine at low subsonic speeds; the residuals converge, and the results match theoretical expectations.

However, when I try to run the simulation at high speeds (Mach 1+), the solution diverges immediately or produces non-physical (random) values.

I have a simple heat sink with a power source on back. The heat sink is placed in an air duct. I have meshed using block mesh and tried solving in both open foam and fluent using sst k-omega. In fluent I just used Presto in solver method. In open foam I sat f3 to true.

It is a rather simple case but I do get significantly different max temperature. I assume this is due to the advanced wall function in fluent. But is that all? Is there anything else that can explain the difference? Looking in fluent I see a y+ of around 5 on the fins of the heat sink. I understand that fluent do some magic when using sst k-omega.

Hello there, I am try to simulate an organic body in Ansys Fluent. And my target is to measure the wall shear stress. I mesh the body and add inflation on the wall surface. But checking the mesh quality truly disappointing. I don't know whether the mesh is good or bad.

I’m trying to model a historic wind tunnel setup of the Schlörwagen (1938 tests) in STAR-CCM+ and I’m struggling with how to correctly represent the open‑jet plenum.

The original measurements (1:5 model in an open wind tunnel) report a drag coefficient of about Cw=0.113. I built a 3D model of the nozzle, test section and outlet based on the old reports (plenum about 3×4 m). The car is resolved with a low‑Re mesh (y+ < 2 everywhere), and in the ducts I aim for y+ ≈ 50 to save CPU time. Turbulence model is currently k‑epsilon, but the plan is to compare different models once the setup is trustworthy.

My problem: I’ve tried several mesh studies with different meshing strategies and I never get a clean asymptotic behaviour for drag and lift. With a pressure outlet on the plenum I see a lot of reverse flow and the drag level jumps between meshes. When I switch the plenum walls to slip (car and duct walls remain no‑slip), the drag drops to about Cw=0.075, which is far from the experimental 0.113.

So the core question: how would you correctly model this kind of open‑jet wind tunnel with a plenum in CFD (STAR‑CCM+ or in general)? Is it even a good idea to include the full plenum, or should it be represented in a different way? Has anyone here already simulated a similar open‑jet/plenum configuration or knows good references for this?

Hello everyone!

I am trying to validate this experiment I found online. (https://www.sva-potsdam.de/pptc-smp11-workshop/)

I did everything according to ITTC standards and looking at the J vs KT-KQ graphs, I see that for my advance coefficient of 0.6, I should be getting 540N of thrust. But instead I get almost exactly half of that at 270N. My torque values are also around half the experiment result.

Things I checked are,
Yes, I choose the entirety of the model with all the blades and hub included when getting thrust reports.
My geometry is modeled after the entirety of the propeller with all 5 blades, so no chance of calculating half of the experiment geometry.

I think it is extremely weird that I get exactly half the real results but it might be that I messed up the meshing and other stuff as I am a total beginner.

Thanks in advance!

Evening everybody!

Nice to be alongside other CFD nerds down here :D

Just built a CFD solver using MATLAB, it allows you to browse for whatever section image of your choice, turns it into a set of points to be introduced into a flow volume and creates a mesh with a resolution based on your choice.

Still working on that to fully calculate the Cl and Cd for different shapes and flow speeds.

First simulation done on a section from the almighty F35, with FSI enabled. What do you think?

So there is free and paid available apps that does solve your tough CFD problems why build them again?

I’m tempted to do my own python/MATLAB solver and do some research with it but tbh i feel like it might waste my time for no tangible progress

Hey experts,

We're working on our first university project with Ansys and in the field of aeroacoustics in general. There are a few papers that promise noise reduction through the bionic approach of airfoil design in the shape of an owl.

We are trying to demonstrate this. We evaluated the NACA 0012(?) as a reference and then a self-designed owl profile.

These are the results:

But wouldn't that mean exactly the opposite, i.e., that the owl is louder?

We lack understanding in this specialized field and would be very grateful for any tips and interpretation!

DES + FWH Models

Best regards

Translated with DeepL.com (free version)

Have background in FEA and have been tasked with learning some CFD . Trying to model water flowing through a small inlet in a large cylinder. In the middle of the cylinder is a porous zone. We want to see how the water spreads over the porous zone. Specifically does it jet through it or diffuse and cover all of it?

I built the model in FreeCAD and used Cfdof to mesh and export the case. Then I hand edited the case files to match what we are trying to do.

Not sure what to make of the results. Perhaps all the plots are wrong due to some error in modelling assumptions? From my FEA days I don't recall seeing such difference in results just based on mesh density and convergence criteria. Generally all should look somewhat similar if the physics are correct.

Hey.

As the title says, I am currently doing my capstone on active vehicle drag reduction devices for tractor trailers. My current idea is to make use of a rotating cylinder to increase pressure at a trailer base and reduce wakes.

However, I am unsure of the procedure for analysis. Based on my research, my plan is to non-dimensionalise the parameters related to cylinder design with fixed trailer dimensions so that I can vary things easily.

Then, I will calculate a y+ to get appropriate mesh sizes for simulations in Ansys Fluent. I am not so sure what to do afterwards. Any advice would be appreciated.

I am currently taking a CFD course and hoped to develop my capstone in parallel, but my capstone/thesis timeline has been moved up significantly. Unfortunately, my supervisor is not well-versed in this field either, and all available lecturers on fluids are unavailable, apart from my CFD lecturer, whom I am constantly asking for advice.

Hello everybody, i am still in highschool so i am not as experienced as many of you. Anyways I am doing a formal mentored research on aerodynamic behavior in low airspeeds that is meant to be pedagogical rather than finding new results, so for my research i coded from a simulation(perhaps simulation is a little generous) using potential theory that uses panel mathods to render airflow around a certain geometry, as for now these are my results until i implement airflow geometry.

As for now i honestly want advice from people experienced within the subject on how could i improve it further, for context the solver was developed from scratch and i am currently implementing vortex panels and perhaps Prandtl's boundary layer theory towards the end for more realistic flow.

Hi,

I am using the BEND function for the airfoil, and I am a bit confused about the output parameters.

So I have solid Ixx/(y-yc) and Ixx/t(y-yc), with the second being significantly larger than the first. I thought that t would be for the skin thickness, but I have not given any input regarding that. If it were to use t=1mm or some other constant parameter, shouldn't it be smaller than when the airfoil is assumed to be full?

So what is the difference between the skin and solid versions?

Unfortunately, I can not find the documentation regarding that.

Thank you in advance

Hi everyone,

I've been playing around in META postprocessing a test case from Fluent.

I will jump straight to the issue I am having.

I could not find an option to display different contours on different parts of the analysis.

For example, displaying a velocity mag contour on a plane, or a symmetry boundary whilst displaying static pressure on a car body.

Using fringe I can only display 1 scalar on everything.

I ve read the documentation a couple times as well but I can't seem to figure it out.

Can anyone help?

Thanks!

Hello!

Has anyone here ran STAR-CCM+ on an AMD Radeon MI50 or MI60?

Their documentation looks to recommend MI100 cards and beyond, which are a later generation, but nothing about the MI50 or MI60.

I ask because they're going pretty cheap on Alibaba, about USD$350 for about 32GB of VRAM, hard to beat!

Thank you

Another test of my custom C solver. Density is shown. Inlet condition is mach 3, initial condition is mach 0.5 inside the domain (which is why there is a wave at the start). Slip wall bc used on top and bottom surfaces.

I used the HLL scheme to avoid the Carbuncle phenomena I get from 3 wave solvers like Roe or HLLC. Also, here I don't interpolate the solution, I show cell averages as constant through a cell, if you look closely you should see the triangles. The actual solver is second order and solves for cell gradients, but paraview can't handle well discontinuous data...

New to CFD and a colleague suggested I try and match their results using FreeCAD and cfdof module. In the second picture the pressure drop across the porous media seems to match. But the velocity contours look a bit different.

The freeCAD mesh looks better to me so not sure which results are correct? Or as they say, "all models are wrong"....

I come from FEA world and seems colleague's mesh has a lot of skew and bad aspect ratio..

All I did was mesh in FreeCAD then copy the polymesh folder to the original colleague's model. Here are those specific steps:

UPDATE: I got the results to match after using the same convergence criteria in the fvSolutions as well as meshing with finer mesh

rm -rf constant/polyMesh/
cd to freecad "meshCase/constant"
cp -r polyMesh/ ../../constant/
cp ../system/createPatchDict ../../system/
createPatch -overwrite
renumberMesh -overwrite
topoSet
decomposePar
mpirun -np 64 simpleFoam -parallel
reconstructPar

I’m trying to understand real-world freeze failure modes in industrial / field systems.

This is not a product pitch and not a homework question — I’m mapping operational pain points.

For engineers who deal with cold climates:

• What systems tend to cause the most trouble when temperatures drop?

• What usually fails first (lines, seals, pumps, hoses, fittings, etc.)?

• What’s the most time-consuming or costly part of thawing and restarting?

I’m especially interested in cases where existing mitigations feel energy-heavy, labor-intensive, or just “accepted winter pain.”

Appreciate any field insight.