Mechanisms and models of the turbulent boundary layers at transcritical conditions
- Northwestern Polytechnical Univ., Xi'an, Shaanxi (China); National Key Laboratory of Aircraft Configuration Design, Xi'an, Shaanxi (China)
- Stanford Univ., CA (United States); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
Computational models for high-pressure transcritical turbulence in wall-modeled large-eddy simulation typically rely on wall-function models to overcome the need for resolving the boundary layer structures. However, the mechanisms and models of turbulent boundary layer at transcritical conditions remain poorly understood since the near-wall flow and heat transfer are significantly affected by the enhanced fluctuations and steep gradients in thermodynamic properties. Here, to address this issue, we study the mechanisms of transcritical turbulent boundary layers and wall-attached models at transcritical conditions. It is shown that the real-fluid variable-property effects are associated with the coupling between the near-wall cycle and the wall-normal coherent motions in the outer layer, resulting in the amplification of turbulent energy in the outer layer and noticeable energy transfer between the log-layer and the outer layer; hence, turbulence in the log-layer is modulated by the outer layer. Based on this underlying physical principle, we propose the characteristic velocity and length scales for the attached eddy at transcritical conditions, and extend the attached eddy model to transcritical turbulent boundary layers by introducing a mixed scaling that incorporates both inner and outer scalings. We show that the new characteristic scales and extended attached-eddy model perform well in characterizing the structures in transcritical turbulent boundary layers.
- Research Organization:
- SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); National Natural Science Foundation of China (NSFC); China Postdoctoral Science Foundation; Scientific Research and Technology Development Program of Guangxi Zhuang Autonomous Region; National Funded Postdoctoral Research
- Grant/Contract Number:
- SC0022222; AC02-76SF00515
- OSTI ID:
- 2584263
- Alternate ID(s):
- OSTI ID: 2474307
- Journal Information:
- Physical Review Fluids (Online), Journal Name: Physical Review Fluids (Online) Journal Issue: 10 Vol. 9; ISSN 2469-990X
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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