Additional independent variables are needed in the least squares finite element method(LSFEM)using C
0
element. An improved method
the least squares isogeometric analysis(LSIGA)was proposed to substitute LSFEM. In LSIGA
the high continuity non-uniform rational B-spline(NURBS)was applied as the basis function and only the primitive variables in the Stokes equation were adopted to define the least squares functional. LSIGA does not need additional independent variables
and it can generate the mesh automatically in analysis and the mesh represents the domain geometry exactly. An incompressible 2D Stokes flow was solved with the present method. The numerical solution agrees well with the analytical solution. The results show that the method proposed is applicable for solving the Stokes equation and its k-refinement increasing the NURBS continuity in analysis has an exponential con
vergence rate.
关键词
Keywords
references
BABUKA I. Error-bounds for finite element method [J]. Numerische Mathematik, 1971, 16(4): 322-333.
BREZZI F, FORTIN M. Mixed and hybrid finite element methods [M]. New York, USA: Springer-Verlag, 1991.
BOCHEV P B, GUNZBURGER M D. Finite element methods of least-squares type [J]. Siam Review, 1998, 40(4): 789-837.
BOCHEV P B, GUNZBURGER M D. A locally conservative mimetic least-squares finite element method for the Stokes equations [J]. Large-Scale Scientific Computing, 2010, 5910: 637-644.
PONTAZA J P. A least-squares finite element formulation for unsteady incompressible flows with improved velocity-pressure coupling [J]. Journal of Computational Physics, 2006, 217(2): 563-588.
PRABHAKAR V, REDDY J N. A stress-based least-squares finite-element model for incompressible Navier-Stokes equations [J]. International Journal for Numerical Methods in Fluids, 2007, 54(11): 1369-1385.
BOCHEV P B, GUNZBURGER M D. Analysis of least-squares finite-element methods for the Stokes equations [J]. Mathematics of Computation, 1994, 63(208): 479-506.
BOCHEV P B, GUNZBURGER M D. Least-squares finite element methods [M]. New York, USA: Springer-Verlag, 2009.
HUGHES T J R, COTTRELL J A, BAZILEVS Y. Isogeometric analysis: CAD, finite elements, NURBS, exact geometry and mesh refinement [J]. Computer Methods in Applied Mechanics and Engineering, 2005, 194(39/40/41): 4135-4195.
PIEGL L A, TILLER W. The NURBS book [M]. New York, USA: Springer-Verlag, 1997.
BENSON D J, BAZILEVS Y, HSU M C, et al. A large deformation, rotation-free, isogeometric shell [J]. Computer Methods in Applied Mechanics and Engineering, 2011, 200(13/14/15/16): 1367-1378.
BUFFA A, FALCO C De, SANGALLI G. Isogeometric analysis: stable elements for the 2D Stokes equation [J]. International Journal for Numerical Methods in Fluids, 2011, 65(11/12): 1407-1422.
ZHU Xuefeng, MA Zhengdong, HU Ping. Nonconforming isogeometric analysis based on NURBS with exact geometry [J]. Chinese Journal of Solid Mechanics, 2012, 33(5): 487-492.