5.2.4. MPMD Examples

5.2.4.1. PMR - Radiation

This example demonstrates a radiation transport problem using Sierra/PMR for an external PMR solve coupled via MPMD. See MPMD Radiation for more discussion on how to setup the Aria and PMR inputs.

5.2.4.1.1. Problem Files

The files required for this example can be downloaded here, or found at $TESTS/aria_rtest/example/training/pmr (where TESTS=/projects/sierra/tests in a CEE environment, or your Sierra test distribution otherwise).

Aria input file

PMR input file

Aria mesh file

PMR mesh file

5.2.4.1.2. Input Deck Modification

To introduce an external PMR solve, an MPMD coupling block is first introduced in the Aria input deck. Here, the PMR solve is repeated every 2nd nonlinear Aria iteration.

# Scope: Sierra > Procedure > Aria Region
Begin MPMD Coupling
  Coupling Type is Radiation
  Begin Radiation Coupling
    Iterations per Radiation Solve is 2
  End Radiation Coupling
End MPMD Coupling

This result is communicated to the Aria region by declaring an XFER equation (see Equation Specification) for Radiation_Transport

# Scope: Sierra > Procedure > Aria Region
EQ Radiation_Transport For rte_scalar_flux On Block_1 Using Q1 With xfer

This result is then fed into the temperature solve via a SRC

# Scope: Sierra > Procedure > Aria Region
EQ Energy For Temperature On block_1 Using Q1 With Diff Src
Source For Energy On block_1 = RTE_FIELD

In order to calculate the boundary intensity field sent to Sierra/PMR, the Emissivity, Transmissivity, and BC Environment Temperature must be defined on all boundary surfaces using surface materials

# Scope: Sierra
Begin Aria Material wall_a
  emissivity                   = Constant e = 0.6
  transmissivity               = Constant t = 0.4
  bc environment temperature   = Constant T = 1000.0
End

Begin Aria Material wall_b
  emissivity                   = Constant e = 0.6
  transmissivity               = Constant t = 0.4
  irradiation                  = FROM_MPMD_FIELD
  bc environment temperature   = Constant T = 0.0
End

Note in this example, the irradiation is also solved from the resulting MPMD solution so that an additional radiation BC can be applied to the surface

BC Flux for Energy on surface_2 = Generalized_Rad

The reader is referred to the PMR user manual for details on how to modify the provided PMR input deck.

The problem can then be launched with the following command

$ mpirun -np 4 aria --mpmd_master --mpi_color 9999 \
    -i aria.i : -np 2 pmr -i pmr.i