HeatEquationSolver

equation_evaluation_frequency

For steady simulations the default value for equation_evaluation_frequency is 10, which means if the flow solver is evaluated at every pseudo step, the heat solver is evaluated every 10 pseudo steps of the flow solution. This parameter essentially controls the feedback frequency from the solid to the fluid. It should always be greater than or equal to the equation_evaluation_frequency of the flow solver.

linear_solver

linear_solver controls the settings of the linear solver. Either absolute_tolerance or relative_tolerance can be used to determine the convergence of the linear solver. Together with max_iterations, they determine how much the heat equation solver residual converges in each pseudo step.