radopt#

Radiosity.radopt(fluxtol='', solver='', maxiter='', toler='', overrlex='', maxfluxiter='', conservation='', **kwargs)#

Specifies Radiosity Solver options.

Mechanical APDL Command: RADOPT

Parameters:
fluxtolstr

Convergence tolerance for radiation flux. Defaults to 0.0001. This value is a relative tolerance.

solverint or str

Choice of solver for radiosity calculation:

  • 0 - Gauss-Seidel iterative solver.

  • 1 - Direct solver.

  • 2 - Jacobi iterative solver (default).

maxiterstr

Maximum number of iterations for the iterative solvers ( SOLVER = 0 or 2). Defaults to 1000.

tolerstr

Convergence tolerance for the iterative solvers ( SOLVER = 0 or 2). Defaults to 0.1.

If TOLER ≥ 0, the value is interpreted as an absolute tolerance. If TOLER < 0, it is interpreted as a relative tolerance.

overrlexstr

Over-relaxation factor applied to the iterative solvers ( SOLVER = 0 or 2). Defaults to 0.1.

maxfluxiterint or str

Maximum number of flux iterations to be performed according to the specified solver type:

  • 0 - If the FULL solver is specified ( thopt,FULL), convergence criteria are monitored and iterations are performed until convergence occurs. If the QUASI solver is specified ( thopt,QUASI), convergence criteria are ignored and one iteration is performed. This value is the default.

  • 1, 2, 3,...N - If the FULL solver is specified ( thopt,FULL), convergence criteria are monitored and iterations are performed until convergence occurs, or until the specified number of iterations has been completed, whichever comes first. If the QUASI solver is specified ( thopt,QUASI), convergence criteria are ignored and the specified number of iterations are completed.

To view MAXFLUXITER usage illustrations, see and.

conservationint or str

Key to account for the midside node temperature of underlying solid elements for radiosity calculations. Under normal circumstations using lower order elements, this option does not need to be activated. However, when using higher elements, you can improve energy conservation by setting CONSERVATION = 1.

  • 0 - Not active (default). The midside node temperatures are not accounted for in the radiosity calculations.

  • 1 - Active. The midside node temperatures are accounted for in the radiosity calculations. To work effectively, CONSERVATION requires a one-to-one correspondance between the surface elements and their underlying solid elements. Therefore, it cannot be activated if the rdec command was issued when generating SURF251 or SURF252 elements.

Notes

The radiation heat flux is linearized, resulting in robust convergence.

The radiation flux norm for FLUXTOL is expressed as:

\[equation not available\]

where i is the pass or iteration number and j is the surface facet for radiation.

For a sufficiently small absolute tolerance value, relative tolerance converges in fewer iterations than absolute tolerance. For a sufficiently large absolute tolerance value, relative tolerance may cause convergence difficulties.

For more information about FLUXTOL and MAXFLUXITER usage, see and in the Thermal Analysis Guide.

In and (under Solving for Temperature and Radiosity Q Q = F:sub:Q equation system via the iterative method.

If TOLER ≥ 0, the iterative solver ( SOLVER = 0 or 2) is converged for maximum value over a different j as shown:

\[equation not available\]

If TOLER < 0, the iterative solver ( SOLVER = 0 or 2) is converged for maximum value over a different j as shown:

\[equation not available\]

where:

  • j = number of radiation facets

  • k = number of iterations ( k = 1 to MAXITER )

The Jacobi iterative solver ( SOLVER = 2) is the only solver choice that runs in a fully distributed parallel fashion. Therefore, it is typically the best choice for optimal performance when running in distributed-memory parallel mode.