Active control of instabilities in laminar boundary-layer flow. Part 1: An overview
Abstract
This paper (the first in a series) focuses on using active-control methods to maintain laminar flow in a region of the flow in which the natural instabilities, if left unattended, lead to turbulent flow. The authors review previous studies that examine wave cancellation (currently the most prominent method) and solve the unsteady, nonlinear Navier-Stokes equations to evaluate this method of controlling instabilities. It is definitely shown that instabilities are controlled by the linear summation of waves (i.e., wave cancellation). Although a mathematically complete method for controlling arbitrary instabilities has been developed (but not yet tested), the review, duplication, and physical explanation of previous studies are important steps for providing an independent verification of those studies, for establishing a framework for subsequent work which will involve automated transition control, and for detailing the phenomena by which the automated studies can be used to expand knowledge of flow control.
- Publication:
-
Final Report Institute for Computer Applications in Science and Engineering
- Pub Date:
- December 1994
- Bibcode:
- 1994icas.rept.....J
- Keywords:
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- Active Control;
- Boundary Layer Control;
- Boundary Layer Flow;
- Boundary Layer Stability;
- Boundary Layer Transition;
- Laminar Boundary Layer;
- Tollmien-Schlichting Waves;
- Laminar Flow;
- Navier-Stokes Equation;
- Wave Attenuation;
- Fluid Mechanics and Heat Transfer