Predicting the Deterioration of Ancient Thai Murals with Ansys CFD

Home to some of Thailand’s finest art and culture, Ayutthaya was established as one of the region’s greatest cities and flourished between the 14th and 18th centuries. It was declared a United Nations Educational, Scientific, and Cultural Organization (UNESCO) World Heritage Site in 1991.

Murals were popular in the ancient Thai royal palace, but sadly, much of Ayutthaya was destroyed by war in 1767. For this reason, an assistant professor at Rajamangala University of Technology Suvarnabhumi in Thailand has embarked on a personal mission to prevent the deterioration of remaining murals using Ansys computational fluid dynamics (CFD).

Challenges

Although the organic pigments used in ancient murals can last for long periods of time, an accumulation of humidity can lead to deterioration. In addition, rising climate change, pollution, and urbanization negatively impact air quality and wind outside many historic monasteries, accelerating the deterioration of the murals and artwork inside. Underground moisture also affects the structure of some of the temples.

Engineering Solutions

To study how environmental conditions impact ancient fine art, Mongkol Kaewbumrung, Ph.D., examined murals at the Wat Na Phramen monastery. He prepared 3D models of art samples using Ansys SpaceClaim and Ansys DesignModeler and constructed mesh in Ansys Fluent Mosaic Meshing. Fluent’s Mosaic Meshing capability enables researchers to transition between varying types of mesh, including polyhedral, hexahedral, and isotropic poly prism elements. The technique reduces the required time for grid creation while maintaining high quality for a transient flow analysis in Ansys Fluent.

Kaewbumrung constructed the grids using more than 12 million units of mesh, including about 5 million polyhedral, 4 million hexahedral, and 3 million isotropic poly prism elements. He leveraged Ansys’ high-performance computing (HPC) and parallel processing capabilities in Fluent and Fluent Mosaic Meshing as well as Ansys EnSight, a data visualization tool that can process models containing hundreds of millions of cells. Boundary conditions for fluidity and humidity distribution were defined using weather data supplied for the central region of Thailand during March and April 2021. 

The CFD simulations revealed a large vortex of humidity and temperature in the monastery — an accumulation due to increased climate change, pollution, and urbanization. Kaewbumrung’s research confirms that humidity plays a role in mural deterioration and illustrates an accurate way to detect and monitor it. This offers critical insight into prevention and maintenance techniques. For example, Kaewbumrung will examine organic colors more closely to improve present-day materials after he discovered that they endure better than chemical-based materials.