Shaping Modal Dynamics for Drag Reduction: A Study of Transition Suppression in Shear Flows
Abstract
The goal of the proposed research is to reduce drag in wall-bounded shear flows by targetingthe linear transient growth mechanism that is responsible for turbulent transition. A newdynamic mode shaping perspective for flow control will be formulated for this purpose.In contrast to conventional transition control strategies, this new perspective will provideflexibility to specify and achieve desirable spatiotemporal characteristics of the controlledflow. Specifically, the proposed research will develop these new methods to determine if,when, and how transient growth can be eliminated or reduced via feedback control in athree-dimensional channel flow. Three complementary research objectives are proposed,each focused on addressing a fundamental challenge associated with dynamic mode shapingof fluid flows. The first objective is to suppress transition by eliminating transient growth.A new dynamic mode orthogonalization strategy will be formulated to realize a controllerthat achieves this aim as closely as possible. The second objective is to formulate a dynamicmode matching strategy that shapes a flow to be less susceptible to transition by controllingit to behave like a flow that is known to be less susceptible to transition. The third objectiveis to formulate data-driven and reduced-order dynamic mode shaping methods that canaccommodate the challenges of high-dimensionality, nonlinearity, and model-uncertainty thatare associated with fluid flow control problems of interest to AFOSR. Each of these objectivesis intended to pave the way to extending the dynamic mode shaping perspective to moregeneral and complex fluid flows. The proposed research will provide, for the first time, ageneral methodology for specifying and realizing a desired spatiotemporal fluid response bymeans of feedback control.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 02, 2017
- Source ID
- FA95501710252
Entities
People
- Maziar S. Hemati
Organizations
- Air Force Office of Scientific Research
- Regents of the University of Minnesota
- United States Air Force