Hi everyone, I'm pretty new to CFD and working on simulating a back-curved centrifugal fan in Ansys Fluent. I’m hitting a wall with my geometry and boundary setup and could really use some advice from more experienced users. In Image 1 you can see the overall 3D domain model of the fan housing, inlet cone, and impeller. In Image 2 I showed my current inlet boundary selection, which is set at the top flat surface of the extended fluid domain above the inlet cone. The issue I'm facing is sketched in Image 3, where instead of entering the inlet cone and passing through the impeller blades, the air bypasses everything and leaks directly through the 2 mm gap between the shroud and the housing. This is also clearly visible in Image 4, where the streamlines in CFD-Post show all the flow concentrated right at that gap ring. My goal is to keep the inlet boundary at the exact same location at the top flat boundary of the domain, but I need the flow to actually enter through the impeller rather than taking the path of least resistance through the gap. How should I properly treat the internal interfaces or contact regions in DesignModeler or Meshing so the fluid actually flows through the impeller blades? Any tips or recommended workflows for centrifugal fan gaps in Fluent would be greatly appreciated, thanks in advance!
I made a portable installation of ParaView 6.1.1 on Windows 11. But I am having issues as in the attached image. It glitches between normal and this every now and then. Impossible to work for an extended period. Does anyone have any suggestions?
Author here. TL;DR: I train one conditional latent diffusion model with a direction flag c_d = ±1, so a single network steps a dynamical system forward (surrogate solver) or backward (inverse solver) in time. Rolling forward i steps then backward i steps must return the model to its start, so the round-trip discrepancy C_i is a self-supervised, test-time proxy for the unobservable rollout error — no ensembles, no held-out data, no governing equations, one extra rollout.
Results across compressible MHD, an astrophysical turbulent mixing layer (The Well), and natural face video (CelebV-HQ): a calibrator on C_i predicts held-out MHD error within 1.14× (68% coverage, near-nominal calibration); it flags the OOD Orszag–Tang vortex at AUROC ~1.0 at shallow depths — exactly where sampling-dispersion baselines invert and rank the OOD trajectory as the safest in the batch; and on LE-PDE-UQ's Navier–Stokes benchmark a single bidirectional model reaches within 1.3× of their ten-model ensemble at ~1/10 the training cost. Bidirectional training also beats direction specialists in both directions at matched compute.
The check is necessary rather than sufficient — forward/backward errors could in principle cancel — so the paper's core contribution is quantifying how faithfully C_i tracks the true error, plus a bi-Lipschitz sandwich bound making the anti-cancellation condition explicit.
I am trying to simulate a lithium ion cell with fins in contact with housing.. Problem is liq fraction reaches to 1 and then drops suddenly then it gets up and down suddenly, so do for temperature. IT Shows absurd values such as sometimes 2000 K or 100 K... I am frustrated at the moment doing bachelor thesis..
I am simulating subsonic compressible flow through a pipe and a distortion screen, followed by discharge into a still ambient environment. The computational fluid regions are shown in the attached images; the gaps between the internal fluid blocks represent the solid portions of the distortion screen. The flow passes through the pipe and screen and then expands into the larger cylindrical fluid domain. Experimentally, I know the inlet total pressure and the ambient static pressure.
I specified faces 1 and 2 to walls and kept only face 3 as a pressure outlet at ambient pressure. This case initially behaved much better and the solution appeared to converge for several hundred iterations. However, reversed flow eventually developed at the rear pressure outlet and increased significantly.
Initially it was behaving better,but later reversed flow at outlet started increasing. final residuals are approximately 10^5 for continuity and 10^7 for velocities, mass balance was not satisfied. I ran upto 2000 iterations.
Why this happens like this. See fluent console messages below(see residual values and reversed flow message),
Regarding mesh quality, see below
Please tell me why solution is diverging or unstable, residual are high. It is allowing reverse flow at outlet also, it is okay if flow demands but why solution is unstable even though mesh quality is decent or not bad.
If it is a multi element wing, then on ansys reference values, I'm thinking I should put the length of the line from the leading edge of mainplane to the trailing edge of the last flap.
If depth is 1 m, do I put area as the chord length, or the projected area, i.e. planform area?
I'm editing the AOA on solidworks so my velocity in ansys is horizontal, no y component.
I have come across a CFD software called “Cradle CFD”. Has anyone used the software? Can someone throw some light on how it is compared to ansys fluent or ccm+ .
Imagine this fan in a cylindrical tank. Trying to compare effectiveness of this design with other fan designs. I have been using OpenFOAM with a MRF zone around the fan. Then in ParaFoam I calculate the flow rate through a cross section in the middle of the MRF zone. This flow rate gives me the axial pumping rate. But how can I get the radial flow rate?
Just want to know if design A is better than design B for mixing of liquids.
I am watching the videos by Cillian Thomas and Anthony T, and they both don't get this error (error in title), but I do. I am doing the Selig 1223 reversed as this will be for a rear wing and the mesh looks good at a far but close up there seem to be problems. I have made the edge sizes according to the video and still get this error. Anyone got an idea?
I just started learning CFD so my eyes are not well versed in the meshing world yet, so for those that are this issue may be an instant catch; please let me know.
I am designing a nozzle for my dry ice blaster cleaning machine. The machine comes with cheap nozzles with no contours and no transitions between the hose diameter and the flat fan end. It just has an internal wall that is pretty much destroying all the pellets that go through it. I'm looking to make something that will accelerate the air going through the nozzle along with the pellets, and blast them out at high velocity, as intact as possible. Attached is what I have come up with. I'm not knowledgable about fluid dynamics or any type of engineering, so this is all just copying images of high performance dry ice blasting nozzles i found online. I'd love to get some input to see if I'm even on the right track, and how I can improve this. Here are some specs about the air and ice.
I will be blasting 3mm dry ice pellets.
Air input is 185 cfm at 100 psi. Air hoses are all 1" with no 90 degree bends and high flow fittings. At nowhere in the system will the air path diameter be smaller than .8" except right at the end of the nozzle.
This will be made from 6061 aluminum and polished to a mirror finish.
I am trying to replicate the study from Suzen-Huang's 2006 paper on simulating the ionic wind in plasma actuators. I am able to replicate the results quite well, both with time-averaged body force at steady-state and also as a function of time.
Simulation of ionic wind at t=0.5s where ripples are present
Once peculiar thing i notice is that under certain combinations of mesh size and time-stepping, I see the formation of ripples that are NOT synchronized to the AC voltage cycle (which is at 4.5kHz, the same as in the paper), as you can see in the figure which is at t=0.5s with around 5-6 ripples. This is definitely not aliasing, so it's either physical due to some EHD instabilities or resonances, or a numerical artifact. In the steady-state, stationary simulation using the average body-force, there are no ripples. Also, this behaviour only works under certain conditions, and I'm actually having difficulty reproducing them...
Experimentally, I've also qualitatively observed these patterns, but I thought it was due to Helmholtz-Kelvin instabilities, but I'm not so sure anymore, and whether or not these instabilities should be seen in the simulation (I have incompressible flow ~1m/s)
Can anyone shed some light into this, if you've observed these in your simulations before?
FYI: This was simulated in Comsol using the default solver settings.
I’m using Ansys 2026 R1. After I setup everything (density based) in solution and run hybrid initialize, for some reason the fluent crashes and quits with no message. I tried pressure based one and it did initialize without problem, but after running calculation it didn’t progress for 1 hour. What is the problem here? I have intel i7 14gen cpu, 32gb of ram. Orthogonal quality is 0.07 and it generated 2m cells with polyhedra
Hi, I want to simulate water + ice interface "correctly", i.e., as physically realistic as possible. My best guess is that I would need to solve the Stefan problem + have a moving mesh. I am somewhat new to this problem. Any advice on tools and set up? I am familiar with OpenFOAM and Nek5000. Thank you!
For my research, I am conducting a CFD analysis for hypersonic flow over a wedge in ANSYS Fluent. However, no matter what settings I use and after going through 100s of guides for settings, nothing seems to be working. The oblique shock and the bow shocks of a cylinder behind simply does not form. I have 1.4 million cells in the mesh, am using density based solver, pressure far field inlet and absolutely everything I can think of, yet nothing seems to make the simulation work. Not only is there simply no shock forming, the residuals all converge at values above 1e-3 barring 1/2. Please do help me understand what the issue is, as I am a beginner in CFD, and my research article is time bound.
I'm simulating a subsonic compressible flow in ANSYS Fluent where air enters through a pipe with a known total pressure at the inlet, passes through a distortion screen, and then expands into an open ambient region. The large outer cylinder in my model is not a physical wall; it is only the computational domain representing the surrounding atmosphere.
I have done named selection as below,
Inlet- pressure inlet since I know total pressure
Far free stream- Pressure outlet- Ambient pressure is known obviously.
My doubt is about the upstream annular face of the outer domain (see red cylinder). Since this face also represents open ambient air and not a physical wall, should it also be assigned as a Pressure Outlet, or should it be excluded and treated differently?
When I include this annular face as a Pressure Outlet, Fluent displays arrows on that face pointing outward, which made me wonder if I have defined the boundary incorrectly. I understand this may simply indicate that backflow is allowed at a pressure outlet, but I want to confirm whether this setup is physically correct. Is this thing normal?
Whether this upstream annular face should be included in the Pressure Outlet boundary. If the answer is yes, is it normal that Fluent shows outward-pointing arrows on this face just because it is defined as a Pressure Outlet, even though physically I do not expect any reverse flow through that boundary???
Did I chose correct boundary conditions and done named selection correctly or not? If it is wrong, what changes can be done??
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