Mar 20, 2015 - 1. Objectives. 2. Introduction. 3. Brain Storming Session. 4. Different Stages/Regions Related to BL Transitions. 5. Instabilities & BL Transitions.
Boundary Layer Transition: An Overview Mazharul Islam, PhD Objectives Introduction Brain Storming Session Different Stages/Regions Related to BL Transitions
Boundary Layer Transition: An Overview Mazharul Islam, PhD
Instabilities & BL Transitions Different Modes of Transitions Important Parameters Affecting Transitions Notable Experimental Investigations Selected Models Summary
University of Calgary, Canada
March 20, 2015
Main Contents Boundary Layer Transition: An Overview
Objectives
1
Objectives
2
Introduction
3
Brain Storming Session
4
Different Stages/Regions Related to BL Transitions
5
Instabilities & BL Transitions
6
Different Modes of Transitions
7
Important Parameters Affecting Transitions
8
Notable Experimental Investigations
9
Selected Models
10
Summary
Introduction Brain Storming Session Different Stages/Regions Related to BL Transitions Instabilities & BL Transitions Different Modes of Transitions Important Parameters Affecting Transitions Notable Experimental Investigations Selected Models Summary Suggested Readings
Objectives of This Presentation Boundary Layer Transition: An Overview
Objectives Introduction Brain Storming Session Different Stages/Regions Related to BL Transitions Instabilities & BL Transitions Different Modes of Transitions Important Parameters Affecting Transitions Notable Experimental Investigations Selected Models Summary Suggested Readings
To learn about instabilities associated with boundary layer (BL) transition. To acquire knowledge about different modes of BL transition. To be informed about three classes of BL transition models.
Introduction Motivation Boundary Layer Transition: An Overview
Critical for computing the drag & skin friction coefficients reasonably for aerodynamic problems;
Objectives Introduction Brain Storming Session Different Stages/Regions Related to BL Transitions Instabilities & BL Transitions Different Modes of Transitions Important Parameters Affecting Transitions Notable Experimental Investigations Selected Models Summary Suggested Readings
Need for a useful model for the open-source/freely available CFD tools like OpenFOAM/foam-extend etc. Still challenging after many decades of research activities and there are scopes for further investigations; Quotes "... most important and probably the most difficult subject in boundary layer work..." (Schetz and Bowersox, 2010) Introduction, Chapter on "Transition To Turbulent Flow" “. . . predicting the onset of either natural or bypass transition is still more of an art than a science (see Savill, 1991 or Seiger et al. For examples).”(Mayle and Schulz, 1997)
Introduction Prominent Researchers Related to Instability/BL Transition Boundary Layer Transition: An Overview
L. Rayleigh (Instability) O. Reynolds (Pioneering experimentation in 1883)
Objectives Introduction Brain Storming Session Different Stages/Regions Related to BL Transitions Instabilities & BL Transitions Different Modes of Transitions Important Parameters Affecting Transitions Notable Experimental Investigations Selected Models Summary Suggested Readings
M.W.F Orr (Hydrodynamic Instability) A. Sommerfeld (Hydrodynamic Instability) L. Prandtl (concept of BL in 1904) G.I. Taylor (Instability) W. Tollmien (T-S Wave) H. Schlichting (T-S Wave) Klebanoff (K-type transition) A.M.O. Smith (original e N model) J.L. van Ingen (original e N model) M. V. Morkovin (Concept of Receptivity, Bypass transition) R.E. Mayle & A. Schulz (laminar kinetic energy equation) .... and many others
Introduction Selected Figures Demonstrating BL Transition Boundary Layer Transition: An Overview
Objectives Introduction Brain Storming Session Different Stages/Regions Related to BL Transitions Instabilities & BL Transitions Different Modes of Transitions Important Parameters Affecting Transitions Notable Experimental Investigations Selected Models Summary Suggested Readings
Figure: Adapted from (Schmid, 2014), Courtesy of Professor, Peter Schmidt, Imperial College, UK
Introduction Selected Figures Demonstrating BL Transition Boundary Layer Transition: An Overview
Objectives Introduction Brain Storming Session Different Stages/Regions Related to BL Transitions Instabilities & BL Transitions Different Modes of Transitions Important Parameters Affecting Transitions Notable Experimental Investigations Selected Models Summary Suggested Readings
Figure: Adapted from (Schmid, 2014), Courtesy of Professor, Peter Schmidt, Imperial College, UK
Introduction Selected Figures Demonstrating BL Transition Boundary Layer Transition: An Overview
Objectives Introduction Brain Storming Session Different Stages/Regions Related to BL Transitions Instabilities & BL Transitions Different Modes of Transitions Important Parameters Affecting Transitions Notable Experimental Investigations Selected Models Summary Suggested Readings
Figure: Adapted from (Schmid, 2014), Courtesy of Professor, Peter Schmidt, Imperial College, UK
Introduction Key Challenges related to BL Transition Boundary Layer Transition: An Overview
Objectives Introduction Brain Storming Session Different Stages/Regions Related to BL Transitions Instabilities & BL Transitions Different Modes of Transitions Important Parameters Affecting Transitions Notable Experimental Investigations Selected Models Summary Suggested Readings
Different types; Affected by numerous parameters; Lack of experimental results of skin-friction coefficients around bodies of practical interests (like airfoils) at low Reynolds numbers (i.e. Re
