Bursting of Laminar Separation Bubbles by O N Ramesh

Explore the intricacies of laminar separation bubbles and their bursting mechanisms in this 30-minute conference talk by O N Ramesh at the International Centre for Theoretical Sciences. Delve into the connection between micro air vehicles (MAVs) and drones, examining schematic representations and pressure distributions of laminar separation bubbles. Investigate key parameters for predicting bursting, including Gaster's parameter and PDCR evaluations. Analyze the causes of bursting through convective and absolute instability in free shear layers, and observe the transition between short and long bubbles. Gain insights from PIV movies and examine the relationship between absolute/convective instability and frequency content. Conclude with a discussion on Reynolds shear stress and a comprehensive summary of the presented concepts.

Syllabus

Turbulence from Angstroms to light years
Bursting of Laminar Separation Bubbles
Acknowledgements
The MAV/Drone Connection
Laminar Separation Bubble : A schematic
Pressure distribution: short/Long/Transitional bubbles
Parameters for the prediction of bursting
Gaster's parameter
PDCR evaluated for the present cases
What causes Bursting?
Convective / Absolute Instability in a free Shear Layer
Amplifier to Oscillator Switch in Mixing Layers
The transition from short to long and vice-versa Occuring via natural disturbance
Absolute/convection nature of instability near bursting
Some movies from PIV
[Video]
Absolute/convectionnection to low/high frequency content.
Reynolds shear stress
The Reynolds shear stress
Summary