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SUPG STABILIZATION PARAMETERS CALCULATED FROM THE QUADRATURE-POINT COMPONENTS OF THE ELEMENT-LEVEL MATRICES ECCOMAS 2004 J. ED AKIN TAYFUN TEZDUYAR Mechanical Engineering, Rice University Houston, Texas akin@rice.edu http://www.mems.rice.edu/TAFSM/. Quadrature-point based defined:.
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SUPG STABILIZATION PARAMETERS CALCULATED FROM THE QUADRATURE-POINT COMPONENTS OF THE ELEMENT-LEVEL MATRICES ECCOMAS 2004 J. ED AKIN TAYFUN TEZDUYAR Mechanical Engineering, Rice University Houston, Texas akin@rice.edu http://www.mems.rice.edu/TAFSM/
Quadrature-point baseddefined: c = ∑qcq ,k~ = ∑qk~q (S1)q = || cq || / || k~q || I = ∑q (S1)q f (cq , k~q , …) Element work arrays:cqandk~q
Contours for mesh Q4:SUGN1 (top), element based S1 (lower left), quadrature-point based S1 (lower right)
Contours for T3 mesh:SUGN1 (top), element basedS1 (lower left), quadrature-point basedS1 (lower right)
Quadrature-point-based S1 contours for: Q4 mesh (top), Q9 mesh (lower left), Q16 mesh (lower right)
Element-based S1 contours for: Q4 mesh (top), Q9 mesh (lower left), Q16 mesh (lower right)
Quadrature-point-based S1 contours for: T3 mesh (top), T6 mesh (lower left), T10 mesh (lower right)
Element-based S1 contours for: T3 mesh (top), T6 mesh (lower left), T10 mesh (lower right)
Constant y-plane solution for S1 from:Q4 mesh (top), T3 mesh (bottom)
Constant y-plane solution for Q4, Q9, Q16 for S1:quadrature-point-based (top), element-based (bottom)
Constant y-plane solution for T3, T6, T10 for S1:quadrature-point-based (top), element-based (bottom)
Constant x-plane solution for quadrature-point-based S1:Q4, Q9, Q16 meshes (top), T3, T6, T10 meshes (bottom)
Discrete Point Values of • The previous contours hide information because they omit the mesh detail and are “smoothed” through different point locations: • Element-based at element centroid • Quadrature-point-based positions • Nodal-point-based positions
Finest T3 mesh followed by zoom-in by center flow rotation point for contour of: T3, T6, T10 elements, Q4, Q8, Q16 elements. Local Tau values are generally proportional to element length through the point, in the direction of the local velocity.
Conclusions Quadrature-point norm based values are efficient to compute. They yield higher values in local regions where the unit vector s or r rapidly changes its direction. The element-based norm is a general framework that automatically accounts for local length scales. Both norm-based methods decrease as the element polynomial order increases. Our favorite: element-based norm
APPENDIX 1Regular T6 mesh uniform flow field test angles: 0 (horizontal edges), 23 (centroid), 45 (long edge), 90 (vertical edges)
APPENDIX 2 Results from previous ways to evaluate: