Under-Relaxation Steady Solver in CONVERGE

PRESENTED BY:
Raju Mandhapati, Senior Principal Engineer
Convergent Science

The Under-Relaxation Steady (URS) solver was introduced in CONVERGE 4.0. Unlike the pseudo-transient steady-state solver, which relies on time marching to reach convergence, the URS solver eliminates physical time-steps entirely. Instead, it replaces the transient term with an under-relaxation term, enabling faster and more robust convergence toward a steady solution. Convergence can be assessed using traditional residual targets or by monitoring key flow variables. Beginning with version 5.0, the variable-omega capability was added, providing improved stability and adaptive convergence behavior. For conjugate heat transfer cases, the URS solver implicitly couples all fluid and solid regions when solving the energy equation, delivering high efficiency for steady-state CHT simulations. The URS approach is highly effective for a wide range of cold-flow applications, including internal flows (e.g., pipes, flow benches), turbomachinery, e-motor cooling, external aerodynamics, and wind-energy simulations. It can also be applied to combustion problems using the SAGE, EDM, or FGM combustion models. This webinar provides an overview of the URS methodology and demonstrates how it can be applied to accelerate steady-state simulations across diverse industrial applications.