High-Reynolds-number fractal signature of nascent turbulence during transition
Abstract
Transition from laminar to turbulent flow over a solid surface is often accompanied by growth and merger of turbulent spots. Our analysis shows that these spots’ boundaries exhibit power-law scaling already during early phases of transition at very moderate Reynolds numbers. The measured fractal dimension, D = 2.36 ± 0.03 , is visible over almost 5 decades and agrees very well with values known from fully turbulent flows, such as for cloud boundaries at much higher Reynolds numbers. Hence, turbulent spots at very moderate Reynolds numbers already contain seeds of high-Reynolds-number geometric scaling behavior. Since analytical tools are typically more easily applicable at low Reynolds numbers, turbulent spots could serve as a convenient setting for developing analytical tools aiming to predict high-Reynolds-number scaling laws in turbulence.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Feb 05, 2020
- Source ID
- 10.1073/pnas.1916636117
Entities
People
- Charles Meneveau
- Tamer A. Zaki
- Zhao Wu
Organizations
- Johns Hopkins University
- National Science Foundation
- Office of Naval Research