Controlling optical distortion from turbulent flow
Turbulent flow bends light. This work builds low-order models of the flow behind a step and uses feedback control to reduce the resulting distortion of a beam. It supports adaptive-optics design for beam control on aircraft.
- Capability
- Aerospace testing, machine learning and data
- Collaborator
- University of Notre Dame
- Method
- PIV, CFD, POD
- Published
- Int. J. Flow Control, 2011; AIAA Journal, 2018
Challenge, method, outcome
Challenge
Density changes in turbulent flow distort a laser beam. An adaptive-optics system needs a flow model it can control.
Method
A POD and wavenet model of the shear layer behind a backward-facing step, built from compressible flow simulations. Direct adaptive and wavenet-ARX feedback controllers were designed with sensors placed at the aperture.
Outcome
Simulations predicted a 35% reduction in optical aberration (2011). A later study reported a 40% reduction in optical path difference using sensors at the aperture (2018).