University of Illinois Urbana-Champaign

Effects of surface corrugation on primary instability modes in wall bound shear flows

Riahi, Daniel N.

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https://hdl.handle.net/2142/112532

Description

Title
Effects of surface corrugation on primary instability modes in wall bound shear flows
Author(s)
Riahi, Daniel N.
Issue Date
1996-08
Keyword(s)
  • Surface Corrugation
  • Primary Instability Modes
  • Wall Bounded Shear Flows
Abstract
A general theory for the effects of boundary corrugation on primary instability modes in wall bounded shear flows is developed for cases where either stationary or nonstationary disturbances, arising from discrete or continuous spectrum of primary modes, are the most critical ones near the onset of the primary instability of shear flows. Depending on the type of the critical disturbances, particular corrugations with certain magnitudes and shapes of their amplitudes and with certain magnitudes and directions of their wave number vectors can be most effective leading to the preference of either single or multi-modal forms of the primary disturbances with multiple scales. For discrete modal disturbances, the resulting steady or slowly oscillating stable basic flow can exhibit rolls or non-regular rectangular patterns, or multiple of such patterns for the cases where the stationary disturbances are the most critical ones. For the cases where the non-stationary disturbances are the most critical ones, the preferred oscillatory stable basic flow can exhibit patterns in the form of rolls, non-regular rectangles, non-regular polygons, or multiple of such patterns. For disturbances with continuous spectrum of modes, the resulting preferred flow patterns can be quite unusual and non-regular and, in particular, can exhibit non-periouicity in the streamwise and in the spanwise directions.
Publisher
Department of Theoretical and Applied Mechanics. College of Engineering. University of Illinois at Urbana-Champaign
Series/Report Name or Number
  • TAM R 831
  • 1996-6018
ISSN
0073-5264
Type of Resource
text
Language
eng
Permalink
http://hdl.handle.net/2142/112532
Copyright and License Information
Copyright 1996 Board of Trustees of the University of Illinois

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Technical Reports - Theoretical and Applied Mechanics (TAM) PRIMARY
TAM technical reports include manuscripts intended for publication, theses judged to have general interest, notes prepared for short courses, symposia compiled from outstanding undergraduate projects, and reports prepared for research-sponsoring agencies.