Spatially developing drag reduction across a finite oscillating wall
Abstract
The spatial evolution of a turbulent boundary layer at Reτ= 652 developing across a finite spanwise oscillating wall is investigated with normalised oscillation period of T+ ≈ 101 and amplitude A+ ≈ 7, yielding a drag reduction of 32\%. The spatial distribution of skin friction is estimated adopting a recently introduced near-wall data nonlinear regression method based on the arctangent function, which circumvents the requirement of high wall-normal resolution to capture the viscous sublayer. The method viability is assessed against reference DNS data, and the trends of measurement errors from experimental data are well reproduced. The local impact of the control action is examined by evaluating the spatial development of scalar fields of turbulence statistics as well as conditional quadrant analysis to link the onset and recovery transients to turbulence events. The boundary layer response is observed to follow an exponential decay law for the skin friction spatial evolution. The decay length-scale corresponds to $0.6$ boundary layer thicknesses δ for the onset transient and 0.9δ for the recovery one. The same exponential fit applied to the Reynolds stresses yields a response within 0.5δ, with the exception of the shear stress peak, that requires a significantly longer distance.
Related
- Thermoresponsive self-oscillating hydrogel: spatially lumped model, relaxation dynamics and mechanical output
- Intercoupling of Segregation and Rheology in Spatially Developing Granular Chute Flows
- The I3322 quantum value is attained spatially but not in finite dimension
- Finite-Size Effects on Symmetry Restoration in a Rotating Scalar System with Spatially Dependent Thermal Self-Energy
- Arbitrary-phase CZ gate and remote readout across spatially separated superconducting nodes
BibTeX
@misc{galli2026spatially,
title = {{Spatially developing drag reduction across a finite oscillating wall}},
author = {Marco Galli and Nicolò Scaiola and Ferdinand F. J. Schrijer and Fulvio Scarano},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.28104},
eprint = {2610.28104},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.28104},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Spatially developing drag reduction across a finite oscillating wall
AU - Marco Galli
AU - Nicolò Scaiola
AU - Ferdinand F. J. Schrijer
AU - Fulvio Scarano
PY - 2026
DA - 2026/10/20
PB - arXiv
DO - 10.48550/arxiv.2610.28104
UR - https://arxiv.org/abs/2610.28104
AB - The spatial evolution of a turbulent boundary layer at Re_τ= 652 developing across a finite spanwise oscillating wall is investigated with normalised oscillation period of T^+ ≈ 101 and amplitude A^+ ≈ 7, yielding a drag reduction of 32\%. The spatial distribution of skin friction is estimated adopting a recently introduced near-wall data nonlinear regression method based on the arctangent function, which circumvents the requirement of high wall-normal resolution to capture the viscous sublayer. The method viability is assessed against reference DNS data, and the trends of measurement errors from experimental data are well reproduced. The local impact of the control action is examined by evaluating the spatial development of scalar fields of turbulence statistics as well as conditional quadrant analysis to link the onset and recovery transients to turbulence events. The boundary layer response is observed to follow an exponential decay law for the skin friction spatial evolution. The decay length-scale corresponds to $0.6$ boundary layer thicknesses δ for the onset transient and 0.9δ for the recovery one. The same exponential fit applied to the Reynolds stresses yields a response within 0.5δ, with the exception of the shear stress peak, that requires a significantly longer distance.
ER -