OpenFOAM Tutorial – Chapter 2 (Part 13): Adjust deltaT for Graded Mesh + mapFields + Run icoFoam скачать в хорошем качестве

OpenFOAM Tutorial – Chapter 2 (Part 13): Adjust deltaT for Graded Mesh + mapFields + Run icoFoam

In Chapter 2 (Part 13), we continue from the graded mesh case (CavityGrade) and do the key stability step: update the time step (deltaT) so the Courant number stays under control after mesh grading. Because the mesh now has smaller cells near the corners, we must use a smaller Δt to keep Co ≲ 1 and maintain solver stability. What you’ll learn in this video ✅ 1) Update deltaT in controlDict (Courant stability) We accept the tutorial result that the smallest cell size ≈ 3 mm, which leads to: deltaT ≈ 0.00345 s (3.45 ms) We also set the run parameters for this short continuation: startTime = 0.7 endTime = 0.8 writeControl = runTime writeInterval = 0.05 ✅ 2) Map fields from CavityFine → CavityGrade To avoid restarting from zero, we map the converged solution: use mapFields with -consistent (same patch names + matching locations) After mapping, a new time folder is created (e.g., 0.7/), and the old 0/ folder is no longer needed. ✅ 3) Run icoFoam and save output to a log file We run the solver and redirect output to a log so we can verify: solver starts from the mapped time new time folders are written Courant number remains below 1 solution converges properly to the end of the run ✅ 4) Visualize updated results in ParaView We reload the case, go to the last time step, and inspect the pressure field for the graded mesh case. What’s next Next, we’ll change the Reynolds number / viscosity and see how the flow behavior changes for higher vs lower viscosity. Keywords (copy/paste) OpenFOAM, icoFoam, Courant number, deltaT, time step, mesh grading, graded mesh, CavityGrade, CavityFine, mapFields, mapFields consistent, controlDict startTime endTime, writeControl runTime, writeInterval, CFD stability, ParaView reload files, cavity tutorial Hashtags #OpenFOAM #CFD #icoFoam #CourantNumber #deltaT #mapFields #MeshGrading #ParaView #ParaFoam #CFDTutorial