Numerical Modeling of Heat Transfer and Thermal Attenuation Lengths in Ventilated Caves

Abstract

<p>Atmospheric temperature variations are characterized by different frequency-modes including yearly and daily fluctuations as well as yearly average temperatures. In a ventilated cave, the thermal amplitude is attenuated with increasing distance from the upper and/or lower cave entrance. Convective heat flux for dry air is exchanged with cave wall and the heat transferred by conduction to the surrounding rock is attenuated within a certain distance. Here, we aim at determining the thermal attenuation length for the different modes along a cave and the surrounding rock. Distribution of amplitude of fluctuations along the cave is specified by using Fourier series expansion for dominant modes. In next steps, the effect of latent heat exchange at the cave wall due to evaporation or condensation will be studied. The main variables controlling thermal perturbations in ventilated caves are recognized and compared with field data by developing a numerical model based on the heat and mass transfer between the rock and the air. Moreover, our model aims to quantify the air and wall temperature profile along the conduit for a one-year. The model calculates water-vapor exchange rate along the cave showing the amount of consumed or produced water by evaporation or condensation along the cave and provides the rock temperature distribution in the surrounding hostrock. Our preliminary results contribute to a better understanding of the long-term cave dynamics and may support a quantitative interpretation of speleothem records.</p>

Modelling heat transfer for assessing the convection length in ventilated caves

“…All the model output files for numerical simulations (Comsol files) are available upon request from the authors and all the field data (including the three instrumented sites) can be found in https://doi.org/10.5281/zenodo.10514555 associated to Sedaghatkish et al (2024).…”

Modeling Heat Transfer for Assessing the Convection Length in Ventilated Caves

“…Text files including the numerical results plotted in Figures 4–9 are available at https://doi.org/10.5281/zenodo.10953068 cited as Sedaghatkish and Doumenc (2024). The Comsol Multiphysics file containing the data and results related to the reference case of Figures 4–6 is also available, but a license of Comsol Multiphysics software is necessary to use it.…”

“…All the field data (including the three instrumented sites) can be found in https://doi.org/10.5281/zenodo.10514555 associated with Sedaghatkish et al. (2024).…”