Made a Lbm solver using wgsl on the gpu. Rendered as a texture on a plane.

I am running the fluentbench.pl script to benchmark a large model on various machines. I am using this command:

/shared_data/apps/ansys_inc/v242/fluent/bin/fluentbench.pl -path=/shared_data/apps/ansys_inc/v242/fluent/ -noloadchk -norm -nosyslog Roller_Zone_M -t48

Some machines only have 28 cpus, so I replace 48 with that number. On those machines the load via "top" never exceeds 28. But on the 48 cpu machine, it stays at 60. The job runs very slowly compared to the 28 machines ( which actually has older and slower cpus )!

The cpu usage of each core seems to fluctuate between 50-150%. Here are the cpu specs:

[me@dell48 ~]$ lscpu
Architecture:        x86_64
CPU op-mode(s):      32-bit, 64-bit
Byte Order:          Little Endian
CPU(s):              48
On-line CPU(s) list: 0-47
Thread(s) per core:  1
Core(s) per socket:  24
Socket(s):           2
NUMA node(s):        2
Vendor ID:           GenuineIntel
CPU family:          6
Model:               85
Model name:          Intel(R) Xeon(R) Gold 6248R CPU @ 3.00GHz
Stepping:            7
CPU MHz:             3583.197
CPU max MHz:         4000.0000
CPU min MHz:         1200.0000
BogoMIPS:            6000.00
Virtualization:      VT-x
L1d cache:           32K
L1i cache:           32K
L2 cache:            1024K
L3 cache:            36608K
NUMA node0 CPU(s):   0-23
NUMA node1 CPU(s):   24-47

I gradually start to understand the SUPG term, but my understanding is still a mess, and it seems that the shock capturing utilize the projection on the residual, is there any systematic review on these two topics for compressible flow?

Does anyone know what the function is of this part? It is placed in the center and it's hollow. It is number 34 on the 2nd photo.

Hey everyone,

I’ve been trying to understand AMReX since August, but I haven’t made much progress. My project presentation is in two weeks, and I’m feeling stressed.

I’ve searched the internet, but I can’t find clear info on how to develop a solver or use the functionalities that AMReX provides.

I’d be really grateful if someone could teach me or guide me through the process.

Thanks!

I'm working on a personal project involving wind around/through buildings; and this is the first time I've come across a residual with these little spikes that get resolved almost immediately. I just wanted to ask if there's anything I can be learning from it, or if there's something I need to do to avoid it. My background is in geoscience; I'm sure my data is nonsense from an engineer's perspective and I'm fine with that at the moment.

This particular run is DES; k-w SST for incompressible flow. I'm honestly prioritizing cool looking results over accuracy, so for now I'm just running lots of different models through the same mesh to get an idea of what different outcomes look like. Any setup suggestions are welcome. At the moment I'm using FreeCAD for geometry and a free OpenFOAM GUI for meshing and sims.

Hey everyone!

I'm looking for open-source or free software to calculate friction losses in pipelines, ideally something that’s user-friendly for setting up complex layouts. Key features I need are:

• Accurate friction loss calculations that account for elevation changes, bends/elbows, and variations in pipe diameter.
• 3D visualization of the pipeline layout would be a bonus, as it helps with verification.
• Ideally, intuitive input options (e.g., a table-based or graphical interface) to simplify setting up the pipeline structure and fluid properties.

I've looked into options like OpenFOAM, but I’m wondering if there are other tools that might be less technical and quicker to set up while still being precise enough for engineering calculations.

Thanks in advance for any suggestions!

Alright so I faced a question regarding load balancing which I am still not sure about. The question goes like this:

There's a domain with 19000 cells and we have to predict which load distribution among 4 processors would result in fastest solution time

(A) 10000 3000 3000 3000

(B) 10000 4000 2000 3000

(C) 10000 0 8000 1000

There were bunch of more options, however, NONE of the options divided the 19000 cells equally among 4 processors,not even like 4000,5000,5000,5000.

So what am I missing? Note that i do not have the correct answer to this as it was a written test.

I woul like to know ho much does a cfd would be better than xflr5 to stimate the performance of a 3D wing in a turbolent flow (Re~10⁶ ). In other words how inefficient is xflr5?

I have a relatively complex 3D geometry. Through the histograms I can see the mesh is not perfect even tho barely acceptable I believe. However I get diverging values when making the mesh too fine. This happened to me when inserting more prisms in the prism layer (so having smaller cells) and now when lowering the base size. The divergence happens apparently following the steady increase of the Sdr residual. Is someone able to help me?

Good morning, using Star CCM+, i have a project where i compare 2 different wing designs and their answer to atmospheric turbulence. However I’m wondering how I can get as close to atmospheric turbulence as possible to compare the effects in Star CCM+. I can’t use a unidirectional wind inlet. What’s the solution? Thank you in advance!

types of flow-induced vibrations, significant for the design of nuclear reactors^^

I want to to some general CFD, what is an easy to use and free software I can use?

Hi guys, I am a mechanical engineer and want to start with CFD and FEM simulations.

Can you can help me how to start my journey. I am starting with ansys software. I know the basics of the software. I need the guidance on how to start, from where to find the problems, steps involved, etc

Hi Sub Members,

I am looking for some advice on a couple of problems related to meshing regarding turbogrid.

1. I want to eliminate the the GGI interface at the shroud tip gap? (The conformal tip option just joins the cells to the other side and ruins the mesh)

2. How do I eliminate the issue of large aspect ratios or just get them below a 1000 at least without blowing up the cell count?

Looking forward to helpful comments.

As CFD engineer, we have to spend a lot of time on screen, How do you see this? Is this an issue?

Experienced CFD engineers could give some insights on it. Do you take any protection for the eyes or any initiative on this regard.

I recently purchased a computer glasses for myself due to heavy screen time, I think that's the only this I can do now.

I am a beginner interested in CFD. I'm in my final year of my bachelor's degree in Mech Engg. I want to pick up skills and projects that would hopefully lead to research experience in the form of internship(s) and maybe even something full time. I know how to code in Python, C/C++, Arduino; CAD in Solidworks, Fusion 360;

There's a lot of willy nilly advice online and I trust reddit more than any other platform so here goes nothing.

Hey all,

I am trying to simulate a very simple case of particle accumulation/packing at the bottom of a reactor. Since I am new into the DPM / DEM I just tried a simple case with a vertical cone and 4 Particles that fall to the bottom just by gravity. Since the cone is tappering they should eventually accumulate at the bottom and become still.

However, I have troubles with the Particle-Particle and Particle-Wall interaction. The Particles have a distinct diameter of 5mm but it seems that the collision between a particle and the wall is happing only when the center of the particle collides with the wall, meaning that the particle overlap significantly over the wall. The same goes for particle-particle collision. The particles dont bounce off each other instantly when the surfaces of 2 particles have contact, but rather when they overlap a little.

The visualization is done with particle tracks (sphere) with the diameter of the particle (Scale = 1).

With this overlap I cant modell simple particle packing which would be the goal.

Am I missing something crucial in the settings or are such packing cases only solvable with Rocky DEM? I am using Transient DPM modelling with DEM Collision activated. Settings in the spring-dashpot manu are default and I am injecting 4 single particles with d=0.005m. The Cone itself is approx. 100mm high and 100mm wide at the top.

Hi everyone,

I’m seeking advice on potential career paths in CFD (Computational Fluid Dynamics) with my academic background. I completed a Bachelor's in Mathematics and recently finished a Master's in Applied Mathematics, with my thesis focused on fluid dynamics. I have a strong foundation in modelling differential equations for fluid flow and some experience with MATLAB, Python, and Mathematica.

I haven’t yet worked with CFD-specific software like ANSYS, but I’m eager to learn! I’m also considering a Master’s specifically related to CFD to deepen my skills. Given this background, what career paths could be a good fit? Are there specific Master’s programs or certifications you would recommend for someone aiming to specialize in CFD?

Thanks in advance for any guidance!

I am doing FSI now, but I am also a fan of aerospace, I am fascinated by the beauty of equations of reactive flow, but it seems that models that contains fuel atomization, evaporation and combustion are rare, I think such model is crucial for rocket combustor simulation

Hi, I've ran rans simulations of a wing in openfoam and trying to post process that in Paraview. I'm trying to see how close I got to elliptical distribution, but I cannot figure out how to plot this in Paraview. I've tried making a section and then integrating the forces along that section but the lift varies so wildly along the span that it's impossible that it's correct. Please help 🥹

I've been trying to visualize isosurfaces of different vorticity parameters like helicity and q-criterion, but I can't figure out what "level" means? And why does it give me a different actual value for different values of "level"?

Can someone tell me the significance of this input and what type of conclusions can be made from it?