General Structure of the Code

In FASTEST3D the real main routine is fmg3d() (s. section 2.1.9, full multi grid 3d). It controls the execution of the FASTEST3D code.

There are three main areas:

1. Reading input data and initialize values
2. Execute the calculations
3. Output of data for postprocessing and restart

Short Description

The global solution algorithm for the coupled set of conservation equations can be summed up as follows:

1. Initialize the field values ($U$, $V$, $W$, $P$, $k$,... etc.) with some (guessed) initial values (typically zero, if no better guess is available);
2. Assemble the momentum equations and solve them to get $U^*$, $V^*$ and $W^*$;
3. Assemble and solve the pressure-correction equation (ref3.51) to get $P'$;
4. Correct the mass fluxes, pressure and nodal velocities using expressions (ref3.48) and (ref3.53);
5. Solve other scalar equations which might be involved;
6. Return to step 2 and repeat, using corrected mass fluxes, velocities and pressure as initial values, until convergence.

In the remainder of this section, a detailed description of the most important subroutines of the FASTEST3D code is given.