Noisy Transitional Flows in Imperfect Channels

TL;DR

This study investigates noisy transitional flows in imperfect millimeter-scale channels using microcantilever sensors, revealing that despite different imperfections, the flows exhibit similar low-order statistics describable by a noisy Landau equation.

Contribution

It introduces a noisy Landau equation model to describe flow transitions in imperfect channels, highlighting the regularizing effect of noise on flow dynamics.

Findings

Low-order flow statistics are similar across different imperfections.

High-order moments differ significantly between channels.

Noise regularizes flow transition singularities.

Abstract

Here, we study noisy transitional flows in imperfect millimeter-scale channels. For probing the flows, we use microcantilever sensors embedded in the channel walls. We perform experiments in two nominally identical channels. The different set of imperfections in the two channels result in two random flows in which high-order moments of near-wall fluctuations differ by orders of magnitude. Surprisingly however, the lowest order statistics in both cases appear qualitatively similar and can be described by a proposed noisy Landau equation for a slow mode. The noise, regardless of its origin, regularizes the Landau singularity of the relaxation time and makes transitions driven by different noise sources appear similar.