Introductory FLUENT Notes Fluent User Services cente ANSYS LUENT v6. 3 December 2006 wwfluentusers. com FLUENT The Spalart-Allmaras Model Spalart-Allmaras is a low-cost RANS model solving a transport equation for a modified eddy viscosity When in modified form the eddy viscosity is easy to resolve near the wall Mainly intended for aerodynamic/turbomachinery applications with mild separation, such as supersonic/transonic flows over airfoils, boundary-layer flows. etc Embodies a relatively new class of one-equation models where it is not necessary to calculate a length scale related to the local shear layer thickness Designed specifically for aerospace applications involving wall-bounded flows Has been shown to give good results for boundary layers subjected to adverse pressure gradients Gaining popularity for turbomachinery applications This model is still relatively new No claim is made regarding its applicability to all types of complex engineering fld OwS Cannot be relied upon to predict the decay of homogeneous, isotropic turbulence C 2006 ANSYS. nc All ANSYS, Inc. Proprietar© 2006 ANSYS, Inc. All rights reserved. 6-10 ANSYS, Inc. Proprietary Fluent User Services Center www.fluentusers.com Introductory FLUENT Notes FLUENT v6.3 December 2006 The Spalart-Allmaras Model ◆ Spalart-Allmaras is a low-cost RANS model solving a transport equation for a modified eddy viscosity. ⚫ When in modified form, the eddy viscosity is easy to resolve near the wall. ◆ Mainly intended for aerodynamic/turbomachinery applications with mild separation, such as supersonic/transonic flows over airfoils, boundary-layer flows, etc. ◆ Embodies a relatively new class of one-equation models where it is not necessary to calculate a length scale related to the local shear layer thickness. ◆ Designed specifically for aerospace applications involving wall-bounded flows. ⚫ Has been shown to give good results for boundary layers subjected to adverse pressure gradients. ⚫ Gaining popularity for turbomachinery applications. ◆ This model is still relatively new. ⚫ No claim is made regarding its applicability to all types of complex engineering flows. ⚫ Cannot be relied upon to predict the decay of homogeneous, isotropic turbulence