@article {Ciletti:2025:0736-2935:168,
title = "Estimation of geometric tortuosity for bulk acoustic absorbers using the heat method",
journal = "INTER-NOISE and NOISE-CON Congress and Conference Proceedings",
parent_itemid = "infobike://ince/incecp",
publishercode ="ince",
year = "2025",
volume = "271",
number = "2",
publication date ="2025-07-25T00:00:00",
pages = "168-178",
itemtype = "ARTICLE",
issn = "0736-2935",
url = "https://ince.publisher.ingentaconnect.com/content/ince/incecp/2025/00000271/00000002/art00018",
doi = "doi:10.3397/NC_2025_0035",
author = "Ciletti, Anthony Vincent and Schneck, William and Spaeth, Peter and Brown, Martha and Sharma, Bhisham",
abstract = "Geometric tortuosity-the ratio of arc length to the straight-line distance between its endpoints-is among the key parameters needed to predict a porous material's acoustic properties. Here, we adapt the heat method, commonly used for surface calculations, to measure tortuosity within
the fluid volume of complex three-dimensional porous lattice unit cells. Our implementation in Python relies on the open-source scikit-fem library to handle finite element operations on a hexahedral mesh of the fluid domain. Adiabatic boundary conditions are applied at both the fluid-solid
interfaces and the unit cell faces, allowing heat to flow from an inlet face through the fluid domain for a brief period. Poisson's equation is then solved using the resulting temperature gradient field. Tortuosity is evaluated at a discharge face opposite the inlet, and path-lines through
the gradient field are visualized. A histogram and spatial map of tortuosity values on the discharge face is generated, revealing a strong dependence on local geometric features, including through-holes. Overall, results show that the heat method offers a viable computational alternative to
estimating the tortuosity of porous acoustical materials.",
}