Title:
A Two-level approach for design optimization of acoustic liners
Abstract:
In this talk, we present a two-level approach for design optimization of acoustic liners panels, which are commonly used to damp engine noise in turbofan engines. The suggested method combines an adjoint-based gradient search algorithm with a global search method applied on a Gaussian process surrogate model. In this way, we effectively exploit the benefits of both approaches to achieve a good compromise between the computational effort and the degree of freedom used in optimization. In the optimization level, a global search is performed with few design parameters employing a Gaussian process surrogate model. In the second level, using the global optimal solution as the initial setting for the refined design vector, an adjoint based gradient search procedure is started. The unsteady discrete adjoint solver, which is the essential ingredient of the optimization framework, has been developed using Algorithmic Differentiation (AD) techniques. The feasibility of the two-level approach is demonstrated by finding the optimal liner parameters of a turbofan engine by-pass duct.