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Updated: Aug 16, 2025
11:03
An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
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Non-ideal gas behavior matters in hydrodynamic instability.
Jie Ren1,2, Markus Kloker3
1Institute of Aerodynamics and Gas Dynamics, University of Stuttgart, Pfaffenwaldring 21, 70569, Stuttgart, Germany. jie.ren@iag.uni-stuttgart.de.
Scientific Reports
|December 21, 2022
Summary
Real-gas effects significantly impact low-speed flow stability, challenging classic Newtonian fluid theory. Understanding these non-ideal thermodynamic influences is crucial for accurate aerodynamic predictions and device design.
Area of Science:
- Fluid dynamics
- Aerodynamics
- Thermodynamics
Background:
- Hydrodynamic instability governs laminar-turbulent transition in fluid flows, essential for aerodynamic device design.
- While hypersonic flows require accounting for thermodynamic/chemical effects, low-speed flows are often simplified using Newtonian fluid theory.
- Classic theory overlooks non-ideal, real-gas effects in low-speed flows, potentially leading to inaccurate predictions.
Purpose of the Study:
- To investigate the role of non-ideal real-gas effects on hydrodynamic instability in low-speed boundary-layer flows.
- To determine if thermodynamic influences, beyond classic theory, affect flow stability at ambient temperatures.
- To analyze the impact of different thermodynamic regimes (subcritical, supercritical, transcritical) on flow stability.
Main Methods:
- Analysis of three-dimensional low-speed boundary-layer flow.
- Inclusion of real-gas effects across subcritical, supercritical, and transcritical thermodynamic regimes.
- Sensitivity studies on perturbation growth rates using full stability equations.
Main Results:
- Non-ideal real-gas effects significantly influence hydrodynamic instability in low-speed flows.
- High sensitivities of perturbation growth rates to thermodynamic inputs were observed.
- The transition-onset location and mechanism are potentially affected by these real-gas effects.
Conclusions:
- Classic Newtonian fluid theory is insufficient for low-speed flows where real-gas effects are present.
- Coupling thermodynamics accurately is essential for understanding flow stability and transition.
- Findings necessitate re-evaluation of aerodynamic models for low-speed applications.
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