A least-squares meshfree method based on the ÿrst-order velocity-pressure-vorticity formulation for two-dimensional incompressible Navier-Stokes problem is presented. The convective term is linearized by successive substitution or Newton's method. The discretization of all governing equations is implemented by the least-squares method. Equal-order moving least-squares approximation is employed with Gauss quadrature in the background cells. The boundary conditions are enforced by the penalty method. The matrix-free element-by-element Jacobi preconditioned conjugate method is applied to solve the discretized linear systems. Cavity ow for steady Navier-Stokes problem and the ow over a square obstacle for time-dependent Navier-Stokes problem are investigated for the presented least-squares meshfree method. The e ects of inaccurate integration on the accuracy of the solution are investigated.

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