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--- kb:turbulence [2012/07/30 23:25] – enviadmin
+++ kb:turbulence [2022/04/04 19:26] (current) – [Turbulence Model in ENVI-met] enviadmin
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 ===== Turbulence Model in ENVI-met =====
+---- this information is outdated ---
 ENVI-met uses the so-called 2-equation Turbulence Kinetic Energy (TKE) Model to predict the turbulence in the air. \\
@@ Line 17: / Line 19: @@
 As the result of the TKE-ε equation Km (via Ke and directly) is used as input data for the next calculation cycle, there is a non-linear feedback loop between the turbulent exchange coefficient and the TKE-ε equation. Once Km begins to be unstable, the TKE-ε equation system will get unstable too, producing even more unstable Km's in the next loop.\\
-To avoid numerical problems, several mechanisms have been introduced in ENVI-met making the turbulence model more reliable:
-  * [[Two-Step Calculation Loops (Initialisation)]]
-  * [[Intelligent Troubleshooting via Relaxation]]
-  * [[Range Limiting]]
-In previous ENVI-met versions, it was suggested to calculate the turbulence field using the "Update" method (Turbulence mode=1, see [[[TURBULENCE]]]-Section). In this mode, the TKE-e equation system was only solved in fixed time intervals until a stationary solution was found. This method was only introduced to keep the model executable on older computers. \\
-Today, we do not suggest to use the "Update" mode any longer!\\
-Recent computers are strong enough to use the "[[[TURBULENCE]|Continuous Mode]]" (2)!\\
-**As the old update method was a huge source of error and frustration, we have decided not to support it any longer in ENVI-met!**
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