Experiments in Transient Growth and Roughness-Induced Bypass Transition
Abstract
The stability of boundary layers has been analyzed most successfully using a normal mode decomposition of the Navier-Stokes equations linearized about a steady basic state. Using this approach, a flow is considered to be unstable if any of its disturbance modes are subject to exponential growth or stable if all of its modes are subject to exponential decay. This analysis leads to the familiar Orr-Sommerfeld/Squire system of equations that can be solved using either a temporal or spatial formulation. The solution describes the growth and decay of Tollmien-Schlichting (TS) waves at various Reynolds numbers, wave numbers and frequencies. For 2-D boundary layers, Squire's Theorem gives the well-known result that 2-D, streamwise-traveling disturbances (i.e., those with spanwise wavenumber beta = 0) are destabilized at lower Reynolds numbers than obliques waves, and consequentially, most of the work done to date on this system has focused on the growth of these 2-D waves because they have been viewed as the most important to the transition process.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 28, 2005
- Accession Number
- ADA433231
Entities
People
- Edward B. White
Organizations
- Case Western Reserve University