February 23, 2022 at 10:55 pmmimozas1Subscriber
I am conducting a Detached Eddy Simulation of a 3D wing.
My main focus for now is capturing cd-cl fluctuations once the wake is being set to periodical motion.
For that reason i have encountered some thought that troubled me. I know since near the wall-boundary the simulation is like RANS, i need y+<=1 for k-omega model. But fot the LES part of the grid i am having trouble defining exactly the size of the grid. I have made a lit.review but found no solid and universal criteria for grid size. The idea i am having is defing that through experimenting-changing-re experimenting.
If anyone has any knowledge on the field of the grid size for the LES part of the DES grid i would be very glad and thankfull to share it.
Again thanks for your time people!February 24, 2022 at 9:34 amRobAnsys EmployeeCheck the courses (top of the page) as at least one covers turbulence and LES. From memory, when the LES model first came out we used to run k-e (would be k-w in your case) to get a flow field and an idea of how turbulent the system was. There may be additional guidance in the Fluent documentation and references quoted there.
February 24, 2022 at 1:01 pmMurari IyengarAnsys EmployeeHi mimozas1 LES requires a finer mesh than those typically used for RANS. In the DES model, based on the turbulent length scaleand grid spacing, RANS/LES model is chosen. For more information, please see the links below.
4.16.1. Overview (ansys.com)
10.1. Estimation of the LES Resolution Quality (ansys.com)
13.2.2. Scale-Resolving Simulation (SRS) Models (ansys.com)
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