TRIO - A general computer code for reactor 3-D flows analysis: Application to a LMFBR hot plenum

TRIO is a code developed at CEA to investigate general incompressible 2D and 3D viscous flows. The full set of NAVIER-STOKES equations associated with the energy equation and a (k - epsilon) turbulence model is solved using either finite-element or or finite-volume method with proper boundary conditions (i.e. wall function technique in turbulent case). TRIO is a set of independently-executable program modules allowing the use of several time integration schemes (implicit/explicit). A ''user-oriented language'' is used to manage data and modules and provides a great flexibility in building up various numberical algorithms. The results presented here are performed with the modified FEM described by GRESHO and AL (cubic and prismatic trilinear elements and semi-implicit time integration scheme). The momentum equations are integrated in time using the forward Euler method and the pressure field is updated by inverting the discretized laplace equation