Numerical Simulations and Control of Flow Past Airfoils at High Angles of Attack

Dr. S. S. Ravindran

NASA Langley Research Center
Hampton, VA

February 12, 1999

Abstract

In flow past airfoils at high angles of attack, one encounters the stall of lift which is related to flow separation from the airfoil. In this talk, we present numerical simulations showing this phenomenon for a NACA0015 airfoil at 1.2 million Reynolds number and compare it with experimental results. Experimental results have shown that the introduction of an oscillating jet at the leading edge of an airfoil can increase its performance at high angles of attack. To improve the performance of this system, the design of an optimal controller will be investigated. In this study we will develop a reduced order model of the airfoil system using a computational fluid dynamics code and use it to design an optimal controller. The reduced order model is defined using the proper orthogonal decomposition technique (POD). Numerical results show that optimally controlled flow results in substantial improvement in lift at post-stall angles of attack.