Continuing Experiments on the Receptivity of Transient Disturbances to Surface Roughness and Freestream Turbulence
Abstract
Transient growth is a boundary-layer instability mechanism that leads to algebraic growth of disturbances generated by surface roughness. Earlier research programs verified that roughness-induced transient disturbances are not optimal and depend critically on the details of the receptivity process. This project seeks to provide a more complete understanding of the receptivity of transient disturbances to a spanwise array of cylindrical roughness elements using biorthogonal decomposition. Both experimental and direct numerical simulation (DNS) data sets are used as inputs to the decomposition procedure. The DNS data is successfully decomposed and provides accurate predictions of downstream disturbance growth. The experimental data is not sufficiently accurate to provide successful decomposition. For this, it appears that at least the spanwise disturbance components must be measured with better accuracy than was achieved in this project. Work will continue on this topic because DNS cannot presently model surfaces with realistic distributed roughness.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 28, 2008
- Accession Number
- ADA589753
Entities
People
- Edward B. White
Organizations
- Texas Engineering Experiment Station