The coupling between inner and outer scales in a zero pressure boundary layer evaluated using a Holder exponent framework

Abstract

This work considers the connectivity between large and small scales in boundary-layer turbulence by formalizing the modulation effect of the small scales by the large in terms of the pointwise Hölder condition for the small scales. We re-investigate a previously published dataset from this perspective and are able to characterize the coupling effectively using the (cross-)correlative relations between the large scale velocity and the small scale Hölder exponents. The nature of this coupling varies as a function of dimensionless distance from the wall based on inner-scaling, y+, as well as on the boundary-layer height, δ. In terms of the fundamental change in the sign of the coupling between ..