Valveless pumping in a fluid-filled closed elastic tube-system: one-dimensional theory with experimental validation

Area of Science:

• Fluid Dynamics
• Soft Matter Physics
• Nonlinear Dynamics

Background:

• Asymmetric elastic structures can exhibit complex fluid behavior.
• Understanding flow generation in confined, deformable systems is crucial for microfluidics and biomechanics.

Purpose of the Study:

• To investigate the generation of unidirectional mean flow in a torus composed of two connected elastic rubber tubes.
• To model and experimentally validate the fluid dynamics within this asymmetric system.

Main Methods:

• Developed a one-dimensional theoretical model by averaging Navier-Stokes equations.
• Analyzed the model using analytical and numerical methods.
• Conducted physical experiments with a real system to validate predictions.

Main Results:

• Demonstrated that periodic compression of asymmetric elastic tubes creates a remarkable unidirectional mean flow.
• Observed that flow characteristics (size, direction) depend intricately on compression frequency, elasticity, and ratio.
• Achieved remarkable agreement between theoretical predictions and experimental results.

Conclusions:

• The 1D model accurately predicts the observed unidirectional flow.
• Theoretical and experimental analyses successfully identified frequencies where flow direction reverses.
• The study provides a validated framework for understanding flow generation in such soft, asymmetric systems.