Data_RSTA-2022-02226_AlamGhosh-original.xls from Unified torque scaling in counter-rotating suspension Taylor–Couette flow

Torque measurements are reported for the Taylor–Couette flow of a neutrally buoyant non-colloidal suspension in the counter-rotation regime upto a particle volume fraction of $\phi =0.2$. A unified scaling relation for the dimensionless torque (the pseudo-Nusselt number) of the form $\mbox {\rm Nu}_{\omega 0} = ( \alpha _0 + \alpha _1{\mbox {\rm Ta}_{1}^*}^{\alpha _2}) \mbox {\rm Ta}( 0) ^{k} {\mu _r( \phi ) }^{n}$ is shown to hold over a range of Taylor number $\mbox {\rm Ta}^{c1} \leq \mbox {\rm Ta}\leq ~10^6$ that covers primary, secondary and tertiary bifurcating states; here, $\mbox {\rm Ta}_1^*= \mbox {\rm Ta}( \phi ) /\mbox {\rm Ta}^{c1}( \phi ) $ is the reduced Taylor number, $\mbox {\rm Ta}^{c1}$ is the critical Taylor number at primary bifurcation and $\mu _r( \phi ) =\mu ( \phi ) /\mu ( 0) $ is the relative viscosity of the suspension. Possible effects of flow transitions and inhomogeneous distribution of particles on torque scaling are discussed.This article is part of the theme issue ‘Taylor–Couette and related flows on the centennial of Taylor’s seminal <i>Philosophical Transactions</i> paper (Part 1)’.