To solve unsteady laminar flow problems,a method of velocity-stress-pressure formulation instead of velocity-vorticitypressure formulation is developed.With Newton's linearized method to linearize convective terms and preconditioned conjugate gradient method to solve equations,unsteady stress formulation of Navier-Stokes equations is solved.Comparison between numerical and experimental results of cavity laminar flow shows that result of stress formulation fits experiment better and has higher accuracy than vorticity formulation.The stress formulation can deal with subgrid stress with least squares finite element method.Comparison with experimental results of cavity turbulent flow reveals feasibility of the method.It lays a firm foundation for large eddy simulation computation.

A numerical investigation is performed to study aerodynamics of a 2D NACA0012 wing and flows in ground effect (IGE). Lift and drag forces are obtained and pressure distribution on airfoil surfaces is recorded at different angles of attack and ground clearances. Viscous flow near ground and air compressibility are taken into account. High lift is obtained as the airfoil is in dose proximity to the ground. The stall angle decreases with reduction of the ground clearance, due to higher adverse pressure gradient. Viscous effect of floor shows less effect on airfoil. Compressibility should be taken into account at lower ground clearances.