NONLINEAR CONTROL OF SHEAR FLOWS

CHAOS THEORY HAS RECENTLY SUGGESTED TWO INNOVATIVE STRATEGIES FOR ACTIVE CONTROL OF GENERAL, NONLINEAR SYSTEMS. BOTH ARE POTENTIALLY APPLICABLE TO THE PROBLEM OF CONTROLLING SHEAR FLOWS, WHETHER IT BE TO ENHANCE OR SUPPRESS THE EFFECTS OF TURBULENCE. EACH MAKES ESSENTIAL USE OF THE NONLINEAR CHARACTER OF THE SYSTEM TO OBTAIN CONTROL. IN MODEL STUDIES OF NONLINEAR OSCILLATORS, CONTROLBY ONE OF THESE METHODS HAS ALREADY PRODUCED DRAMATICALLY BETTER RESULTS THEN TRADITIONAL LINEAR METHODS. THE QUESTION OF WHETHER THESE CONTROL SCHEMES BE MADE TO WORK IN BOUNDED AND UNBOUNDED SHEAR LAYERS WILL BE ADDRESSED BY THIS PROJECT. WORK WILL BE DONE TO DETERMINE THE FEASIBILITY OF THEIR APPLICATION, TO JUDGE THE SUITABILITY OF EACH METHOD IN CLOSED AND OPEN FLOWS, TO SUGGEST GUIDELINES FOR THEIR IMPLEMENTATION, AND TO TEST THEM BOTH ON A MODEL PROBLEM THAT CAN DISPLAY THE MATHEMATICAL CHARACTER OF EITHER FULLY DEVELOPED OR TRANSITIONING FLOWS. SUCCESS IN THIS RESEARCH WOULD POINT THE WAY TO DEVELOPMENT AND TESTING OF NONLINEAR FLOW CONTROL SCHEMES CAPABLE OF SUBSTANTIAL SKIN-FRICTION AND HEAT-TRANSFER REDUCTIONS AT WALLS AND MIXING ENHANCEMENT IN SHEAR LAYERS AND JETS. CHAOS THEORY HAS RECENTLY SUGGESTED TWO INNOVATIVE STRATEGIES FOR ACTIVE CONTROL OF GENERAL, NONLINEAR SYSTEMS. BOTH ARE POTENTIALLY APPLICABLE TO THE PROBLEM OF CONTROLLING SHEAR FLOWS, WHETHER IT BE TO ENHANCE OR SUPPRESS THE EFFECTS OF TURBULENCE. EACH MAKES ESSENTIAL USE OF THE NONLINEAR CHARACTER OF THE SYSTEM TO OBTAIN CONTROL. IN MODEL STUDIES OF NONLINEAR OSCILLATORS, CONTROLBY ONE OF THESE METHODS HAS ALREADY PRODUCED DRAMATICALLY BETTER RESULTS THEN TRADITIONAL LINEAR METHODS. THE QUESTION OF WHETHER THESE CONTROL SCHEMES BE MADE TO WORK IN BOUNDED AND UNBOUNDED SHEAR LAYERS WILL BE ADDRESSED BY THIS PROJECT. WORK WILL BE DONE TO DETERMINE THE FEASIBILITY OF THEIR APPLICATION, TO JUDGE THE SUITABILITY OF EACH METHOD IN CLOSED AND OPEN FLOWS, TO SUGGEST GUIDELINES FOR THEIR IMPLEMENTATION, AND TO TEST THEM BOTH ON A MODEL PROBLEM THAT CAN DISPLAY THE MATHEMATICAL CHARACTER OF EITHER FULLY DEVELOPED OR TRANSITIONING FLOWS. SUCCESS IN THIS RESEARCH WOULD POINT THE WAY TO DEVELOPMENT AND TESTING OF NONLINEAR FLOW CONTROL SCHEMES CAPABLE OF SUBSTANTIAL SKIN-FRICTION AND HEAT-TRANSFER REDUCTIONS AT WALLS AND MIXING ENHANCEMENT IN SHEAR LAYERS AND JETS.