{"id":171061,"date":"2023-06-05T07:05:36","date_gmt":"2023-06-05T07:05:36","guid":{"rendered":"\/knowledge\/forums\/topic\/why-does-the-shielding-function-for-sbes-differ-from-the-blending-function-for-des-model-using-the-sbes-model\/"},"modified":"2023-07-31T12:29:58","modified_gmt":"2023-07-31T12:29:58","slug":"why-does-the-shielding-function-for-sbes-differ-from-the-blending-function-for-des-model-using-the-sbes-model","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/why-does-the-shielding-function-for-sbes-differ-from-the-blending-function-for-des-model-using-the-sbes-model\/","title":{"rendered":"Why does the “Shielding function for SBES” differ from the “Blending Function for DES model” using the SBES model"},"content":{"rendered":"

When running the SBES model, the “Shielding function for SBES” switches between the RANS (=1) and the LES (=0) region. The “Blending Function for DES model” does not enter into the turbulence model, but switches the numerical treatment from Upwind Biased (=1) to Central difference (=0). The name is historic – it should be called “Blending Function for Numerics”. The numerics blending is taken over from the DES model (CFX-Thoery documentation: 2.6.4 “Discretisation of the Advection Terms). A closer agreement of the numerics blending to the enhanced model blending of the SBES formulation can be enforced by changing the default value of the model parameter: C DES for k epsilon Regime = 0 (default is 0.61) RULES: SINGLETON: SBES COEFFICIENTS Solver Name = SBES Description = Controls blending between LES and RANS for SBES turbulence model. Optional Parameter List = C Shielded DES, Csdes, C DES for k omega Regime, C DES for k epsilon Regime END END FLOW: Flow Analysis DOMAIN: fluid FLUID MODELS: TURBULENCE MODEL: Option = SBES SST SBES COEFFICIENTS: C DES for k epsilon Regime = 0 END END END END END<\/p>\n","protected":false},"template":"","class_list":["post-171061","topic","type-topic","status-publish","hentry","topic-tag-18-1","topic-tag-cfx","topic-tag-des","topic-tag-fluid-dynamics","topic-tag-les-des-sas","topic-tag-sbes","topic-tag-shielding-function","topic-tag-turbulence"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t