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Turbulent Drag Reduction by a Near Wall Surface Tension Active Interface.
Somayeh Ahmadi1,2, Alessio Roccon1,2, Francesco Zonta1
11Institute of Fluid Mechanics and Heat Transfer, TU Wien, Vienna, Austria.
Flow, Turbulence and Combustion
|August 3, 2018
Summary
This study investigates turbulence modulation in stratified two-phase flow. The liquid-liquid interface significantly alters turbulence, reducing wall shear stress and creating recirculation zones, especially with varying viscosity ratios.
Area of Science:
- Fluid Dynamics
- Turbulence Research
- Multiphase Flow
Background:
- Stratified two-phase flows are common in industrial applications.
- Understanding turbulence modulation at interfaces is crucial for process optimization.
- Previous studies often simplify interfacial dynamics or viscosity effects.
Purpose of the Study:
- To investigate turbulence modulation in a viscosity-stratified two-phase flow.
- To analyze the impact of viscosity ratio on turbulence near a liquid-liquid interface.
- To simulate interfacial phenomena using advanced computational methods.
Main Methods:
- Direct Numerical Simulation (DNS) of turbulence.
- Phase Field Method (PFM) for interfacial phenomena.
- Simulations in a closed rectangular channel with an imposed pressure gradient.
Main Results:
- A decrease in wall-shear stress compared to single-phase flow.
- Significant turbulence modulation near the interface, extending to the top wall.
- Observed local shear stress inversions and flow recirculation regions.
- Results depend on interface deformability and viscosity ratio (λ).
Conclusions:
- The liquid-liquid interface strongly modulates turbulence in stratified flows.
- Viscosity stratification plays a key role in turbulence behavior and flow structures.
- The findings have implications for managing flow dynamics in stratified systems.
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