Matthias Heinkenschloss - Research

Optimal Control of Flow Induced Noise

A motivating application is the control of flow induced noise in rotorcrafts. As a rotorcraft descends for landing, the trailing vortices from the rotor-blade tips can interact with subsequent blades leading to a high amplitude, impulsive sound. This phenomenon is referred to as Blade-Vortex Interaction (BVI) and, when it occurs, it often dominates other rotorcraft noise sources. A potential means of reducing BVI noise is through on-blade controls such as suction/blowing, micro-flaps/jets, and smart structures. However, since the fabrication and implementation of such systems is expensive, efficient and accurate numerical simulations of noise control systems are required in order to understand the relevant physics and to evaluate and optimize different control strategies before committing them to hardware. Recent advances in numerical algorithms and computer performance have enabled the computational simulation of flow induced noise. However, to date, these aeroacoustic simulations have been limited to single-run studies that focus on the mechanisms of flow induced sound generation.

To goal of this research is the integration of simulation tools for aero acoustic systems with large-scale optimization algorithms. To accomplish this goal, several fundamental research questions must be addressed, such as

• the specification of control and state space and formulation of the optimization problem,
• the formulation and solution of adjoint equations for time-dependent compressible Navier-Stokes equations (describing the near field),
• the formulation and solution of adjoint equations for the coupled near field - far field system,
• use of a near field - far field domain decomposition within the optimization.

This research is funded by the Texas Board of Higher Education through a joint ATP grant with Dr. S. S. Collis.