Controlling Heat Transport and Flow Structures in Thermal Turbulence Using Ratchet Surfaces

Hechuan Jiang, Xiaojue Zhu, Varghese Mathai, Roberto Verzicco, Detlef Lohse, Chao Sun (Corresponding Author)

Research output: Contribution to journalArticleAcademicpeer-review

10 Citations (Scopus)
88 Downloads (Pure)

Abstract

In this combined experimental and numerical study on thermally driven turbulence in a rectangular cell, the global heat transport and the coherent flow structures are controlled with an asymmetric ratchetlike roughness on the top and bottom plates. We show that, by means of symmetry breaking due to the presence of the ratchet structures on the conducting plates, the orientation of the large scale circulation roll (LSCR) can be locked to a preferred direction even when the cell is perfectly leveled out. By introducing a small tilt to the system, we show that the LSCR orientation can be tuned and controlled. The two different orientations of LSCR give two quite different heat transport efficiencies, indicating that heat transport is sensitive to the LSCR direction over the asymmetric roughness structure. Through a quantitative analysis of the dynamics of thermal plume emissions and the orientation of the LSCR over the asymmetric structure, we provide a physical explanation for these findings. The current work has important implications for passive and active flow control in engineering, biofluid dynamics, and geophysical flows.

Original languageEnglish
Article number044501
JournalPhysical review letters
Volume120
Issue number4
DOIs
Publication statusPublished - 26 Jan 2018

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