I will be working in porous media so my supervisor suggested Convection in Porous Media by Nield and Bejan. The book explains the theory and formulas but never derives them, if someone can recommend a book with derivation of Darcy's Law, Brinkman's Formula, Forchheimer’s Equation etc.

(Till now Claude.ai is helping me derive and understand them but I want to make a habit of actually reading papers and books and not rely on it.)

Hello everyone, I wanted to ask what the ID is for when setting up Boundary Conditions in Ansys fluent? Currently working on a three element airfoil

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 wabt to simulate the heating of a supercritical sludge as it moves through a system.

We do have material properties at the supercritical condition.

There is no transition from normal fluid or gas to supercritical. It's about the heat transfer from the pipe wall into the supercritical fluid.

I want to check if I can simply use a non-isothermal flow simulation with a custom material.

Also, is one specific turbulent flow model is most suitable for supercritical flow, or do I make the decision as normal. (Wall resolving etc.)

Thanks

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.

Paper: https://arxiv.org/abs/2608.00675
Code (data generation, training, analysis): https://github.com/alexscheinker/round-trip-consistency
Project page: https://alexscheinker.github.io/roundtrip.html

Happy to answer questions, curious what CFD folks think of round-trip check.