The instability and transition to turbulence in flows through compliant-walled conduits reveals unique destabilization mechanisms compared to rigid-walled channels, with significant implications for engineering and physiological applications.
Prof. Kumaran’s group has investigated the transition to turbulence in flows through soft-walled conduits, uncovering distinct destabilization mechanisms compared to rigid-walled channels. They identified that the stability of these flows is governed by two key dimensionless parameters: the Reynolds number and a parameter representing the elasticity of the wall. Notably, they discovered that at low Reynolds numbers, the flow becomes unstable when a specific dimensionless parameter exceeds a critical value, a phenomenon well-documented in Couette flow but less understood in pressure-driven flows.
At higher Reynolds numbers, two instability modes were predicted: the inviscid mode, characterized by an internal viscous layer, and the wall mode, involving a viscous layer at the wall. Experimental observations confirmed these modes at much lower Reynolds numbers than expected, indicating significant wall deformation impacts. The study’s insights are crucial for applications in marine and aerospace engineering, where drag reduction is desired, and in physiological flows, where enhanced mixing due to turbulence can improve transport processes. This research bridges theoretical predictions with experimental evidence, advancing our understanding of fluid dynamics in compliant-walled conduits.
Reference:
Kumaran V, Stability and the transition to turbulence in the flow through conduits with compliant walls, J. Fluid Mech. (2021)
