Modeling airflow inside and around hoods used for pneumatic control of pest insects .1. Development of a finite element model

A two-dimensional finite element model to simulate airflow inside and around hoods used for pneumatic control of pest insects is presented. The model is based on the 2-D Navier-Stokes equations. The Stream Upwind Petrov-Galerkin method (SUPG) is used to improve the modeling of the highly convective zones. The contour element concept allows a more accurate simulation of the effects of the boundary layer in the immediate proximity of the walls. Three different elements are used to discretize the modelled surfaces and domains: a nine-node quadrilateral, a six-node triangle, and a three-node linear. These elements have three degrees of freedom per summit node (u, v, p), the two components of the air velocity Vector and the static pressure respectively, and two degrees of freedom per middle node (u, v). The numerical scheme of resolution relies on the use of the Newton-Raphson method. Preliminary tests show the potential of the model for simulating airflow under different conditions.