User
Write something
IDDES simulation in OpenFOAM diverging due to CFL instability
Hi everyone, I’m working on an IDDES simulation in OpenFOAM for a Formula car. My RANS simulation runs fine, and I’d like to use mapFields to take that solution as the initial condition for the IDDES run. From my understanding this should make sense, but please correct me if I’m wrong. I’ve also read that meshes designed for RANS are usually not suitable for LES. Would the same be true for IDDES? If so, what kind of modifications would be necessary? At this point I’m not really sure how to proceed. I’ve tried different setups, but the simulation always blows up. Below are the parameters I’ve modified in case someone can give me some guidance. The main issue I’m facing is with the Courant number. Should it always be < 1 for IDDES? Here’s how I tried to control it in controlDict: runTimeModifiable true; // allow controlDict to be read at each timestep adjustTimeStep true; // allow timestep to change based on maxCo deltaT 2e-6; // initial timestep value, adjustable at each iteration maxCo 1.0; // maximum CFL, deltaT changes based on this maxDeltaT 0.05; // upper limit for deltaT This gives acceptable values at the beginning, but after a while the CFL starts growing uncontrollably and the simulation diverges. Other parameters I’ve set are: LESModel: kOmegaSSTIDDES delta: IDDESDelta In fvSchemes: div(phi,U) Gauss DEShybrid linear // scheme 1 linearUpwind grad(U) // scheme 2 hmax 0.65 // DES coefficient, typically = 0.65 1 // Reference velocity scale 0.028 // Reference length scale 0 // Minimum sigma limit (0-1) 1 // Maximum sigma limit (0-1) 1; // B function limiter, usually 1e-03 div(phi,k) bounded Gauss upwind; div(phi,omega) bounded Gauss upwind; div((nuEff*dev2(T(grad(U))))) Gauss linear; Solver: PIMPLE In fvSolutions (under-relaxation factors): fields { p 0.3; } equations { U 0.7; k 0.7; omega 0.7; "(U|k|omega)Final" 1.0; } Any advice on how to stabilize the simulation or set this up properly would be really appreciated. Thanks in advance!
0
0
Seeking Expertise in Combustion Reactions
Hello everyone, I'm looking for someone with expertise in chemical reactions, specifically combustion. I need assistance in discussing and validating some chemical reaction calculations. Your help would be greatly appreciated! Thank you!
0
0
Motorcycle Thermal Management and Aerodynamics
Motorcycles lose 20% of performance due to the poor Aerodynamics. The engine is the heart of motorcycle and heat ; it is an inevitable byproduct. Without proper thermal management, overheating can lead to : → Inefficiency → Performance loss → Mechanical failure Some cooling systems like liquid cooling, advanced radiators, and smart airflow channels help motorbikes dissipate heat efficiently. And when we talk about Aerodynamics, It's not just about achieving top speed. It's about : → Balance → Stability → Rider Efficiency Streamlined body designs reduce drag. And CFD helps in refining the shape for optimal airflow. But why do they matter? → Poor thermal management affects engine performance. → Poor Aerodynamics increase strain on the engine. → And when they both are combined they diminish fuel efficiency and rider comfort. When both systems work in harmony : → Motorcycles become more fuel efficient, stable at high speeds and resilient in demanding conditions. Video source : https://www.youtube.com/shorts/bXrVoKPK9rA
2
0
Sarah's new job
I am happy to announce that I have started a new job position as Lead Generation Executive at AsRa Tech. As part of this job, I’ll be: ✔️ Researching and identifying new opportunities in the market ✔️ Building connections with potential clients ✔️ Collaborating with the team to drive growth for the company. If you are in the Aerospace, Automotive, or other industry and want to collaborate, feel free to contact me. Here's a link to my LinkedIn ID: www.linkedin.com/in/sarah-mirza123
Sarah's new job
FREE Ansys Learning
Anybody Interested in FREE Ansys Training? Hi CFD Community, I am back with another best suggestion for Students, who are interested in learning Ansys. With the help of this course you'll be able to understand the basics of Ansys interface in ONLY 10 DAYS. Whether you are a student or a professional, this is one of the best beginner friendly course for you. Link : https://www.youtube.com/watch?v=jdDKjKlIOBQ&list=PLaDFdVzW8u83bcwy0VtG1JnNUDyRn0I00 Youtube Channel : Simulation Tech Hub
FREE Ansys Learning
1-30 of 79
powered by
CFD Dose
skool.com/cfd-dose-5227
Making Computational Fluid Dynamics (CFD) fun to everyone!
Build your own community
Bring people together around your passion and get paid.
Powered by