5.2.1.5. Directed Energy (Laser) Example

The directed energy source block provides a convenient way of defining a source or flux from a moving laser. This example shows how to add a Gaussian weld flux that moves across a domain.

5.2.1.5.1. Problem Files

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

Input File

Mesh

5.2.1.5.2. Input Deck Modification

The only things needed to add a laser flux are a path function for the movement of the laser and a BEGIN DIRECTED ENERGY block in the Aria region or thermal equation system.

Define a multi-column function for the laser path (at the Sierra level). The columns define the laser spot location and orientation over time.
# Sierra level
Begin Definition for Function PATH3
  Type is multicolumn piecewise linear
  Column Titles Time X Y Z NX NY NZ
  Begin Values
    75.0   0.16 -0.4333    -0.52   0.      0.    -1.0
    150.0  1.5  -0.1624875 -0.52   0.      0.    -1.0
  End
End
Note

Unlike user functions used for material properties, laser path functions do not clip time to the function domain. Instead, the laser is off outside the time bounds of the function.

Add a directed energy block in the Aria region or thermal equation system
# Aria Region level
BEGIN DIRECTED ENERGY MODEL bc3
  laser_power = CONSTANT Value=1082.0

  add surface surface_2
  Origin and Normal function = path3

  BEGIN Gaussian Power Weld Flux
    efficiency = 1.0
    beam diameter = 0.20
    effective beam diameter = 0.18
  END
END

This will produce a flux on surface_2 based on the power and path information provided in the block above. It can be post-processed with the following command

Postprocess value of expression energy_flux on surface_2 as my_flux

or, if you have multiple fluxes on that surface and want only the laser contribution

Postprocess value of expression energy_flux on surface_2 model gaussian_power_weld as my_flux

The same type of post-processor can be applied to laser sources, as

Postprocess value of expression energy_source on block_1 as my_source

with the same ability to restrict the post-processor to the specific model when needed.