Numerical Simulation of Active Control of Boundary Layer Transition
Abstract
A numerical model has been developed for investigating boundary layer transition control for a two-dimensional flat plate boundary layer. Control of a periodically forced boundary layer in an incompressible fluid is studied using surface heating techniques. The spatially evolving boundary layer is simulated. Navier-Stokes and energy equations are integrated using a fully implicit finite difference/spectral method. The Navier-Stokes equations are in vorticity- velocity form and are coupled with the energy equation through the viscosity dependence on temperature. Both passive and active methods of control by surface heating are investigated. In passive control methods, wall heating is employed to alter the stability characteristics of the mean flow. Both uniform and nonuniform surface temperature distributions are studied. With active control, temperature perturbations are introduced locally along finite heater strips to directly attenuate the instability waves in the flow. A feedback control loop is employed in which a downstream sensor is used to monitor wall shear stress fluctuations. Passive control of small amplitude two-dimensional Tollmien- Schlichting waves and three-dimensional oblique waves are numerically simulated with both uniform and nonuniform passive heating applied. Strong reductions in both amplitude levels and amplification rates are achieved. Active control of small amplitude two-dimensional and three-dimensional disturbances is also numerically simulated. With proper phase control, in phase reinforcement and out of phase attenuation is demonstrated. (KR)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1989
- Accession Number
- ADA221659
Entities
People
- Hermann F. Fasel
- Linda D. Kral
Organizations
- University of Arizona