Cobalt Version 4.0 was released in June, 2007. The enhancements above and beyond Version 3.0 include, but are not limited to:
Overset grid capability is available as an additional, separately licensed module.
Added the thermally perfect, calorically imperfect, gas equation of state.
The exact Riemann solver is replaced with an in-house developed method to improve the capture of slowly moving and strong normal shocks, while retaining the advantages inherent to Riemann-based inviscid flux functions.
Significant improvements made to the inviscid flux limiter.
Added the blade element rotor boundary condition, available with and without blade tracking.
Added the oscillatory inflow/outflow boundary condition class.
The corrected mass flow sink boundary condition was upgraded to handle supersonic outflow; prior versions were valid only for subsonic outflow.
The total pressure and temperature source boundary condition was improved.
The temporal damping ‘functions’ were improved. The user-specified temporal damping coefficients can be often reduced by a factor of two from previous versions; this improves temporal accuracy for time-dependent simulations and convergence rate for steady-state simulations.
Several bugs were eliminated; majority of bugs resided in boundary conditions when using the equilibrium air equation of state and in various rigid-body motions. A major bug was removed from the axi-symmetric viscous source terms.