Simulating jet exhaust plumes for optical propagation calculations

Laser beam propagation in severe environments such as a jet engine exhaust may influence performance of Airborne Optical Systems such as Missile Early Warning Systems or Directed Infrared Countermeasures. Laser beam propagation in close vicinity of the engine plume causes performance degradation due to beam wander, and beam broadening effects. In this study aero-optical effects are studied based on four CFD simulations of the same engine geometry. The CFD simulations encompasses ReynoldsAveraged Navier-Stokes (RANS), Large Eddy Simulation (LES) and hybrid RANS-LES methods, as well as different spatial resolution for the LES simulations. The CFD simulation results are used to compute estimates on laser beam wander and laser beam profile after passage of the jet.