InterPore2026

Reducing Confinement-Induced Layering in Random Packings via Sinusoidal Wall Corrugation

21 May 2026, 10:05

1h 30m

Poster Presentation (MS09) Pore-Scale Physics and Modeling Poster

Speaker

Paweł Niegodajew (Department of Thermal Machinery, Czestochowa University of Technology)

Description

Wall-induced ordering in randomly packed particle beds remains a central challenge for porous systems confined by cylindrical containers. Smooth walls promote radial layering and oscillatory void-fraction patterns that decay slowly into the bulk and can compromise flow uniformity and, in reactive systems, overall performance. Although the wall effect has been extensively characterized, practical geometric strategies to attenuate it are still limited.

This study investigates whether sinusoidal corrugation of a cylindrical wall can disrupt near-wall ordering and promote more homogeneous random packings. Random beds of mono-sized spherical particles are generated in columns whose walls feature regular sinusoidal undulations. The objective is to quantify how wall structuring modifies packing organisation and radial porosity structure relative to a smooth-wall reference, and to identify corrugation geometries that most effectively suppress confinement-driven layering.

To assess corrugation performance, two complementary criteria are applied. First, packing disorder is evaluated using a configurational entropy criterion, defined as the Shannon entropy of particle-centre projections on the column base and reported as an entropy gain compared to the uncorrugated wall [1]. This metric captures how strongly wall structuring increases the spatial randomness of particle arrangements. Second, the remaining near-wall heterogeneity is quantified through two normalised void-fraction variability criteria: the normalised standard deviation of local void fraction in the wall zone and in the transition zone. These region-specific measures track how corrugation reduces void fraction oscillations adjacent to the wall and how rapidly bulk-like uniformity is recovered.

Across the investigated bed geometries, sinusoidal wall corrugation is found to systematically alter near-wall packing, weaken radial layering, and reduce void-fraction oscillations extending into the bed. Appropriately scaled corrugation leads to smoother radial porosity profiles and a more gradual transition from the wall region to the bulk, indicating a clear mitigation of wall-induced ordering. The results demonstrate that engineered sinusoidal surface structuring offers a practical route to homogenising random packed beds, with direct relevance to applications where uniform packing and flow distribution are critical.

Acknowledgements
The investigation was supported by the Polish National Science Centre under Grant No. UMO-2023/51/B/ST8/01624.

References
[1] Marek, M., Wilczyński, M., Durajski, A. P., & Niegodajew, P. (2025). Preventing near-wall particles’ ordering in narrow random packed beds of spheres. Advanced Powder Technology, 36(11), 105060.