Analysis of sand-loaded air flow erosion in heritage sites by Computational Fluid Dynamics: Method and damage prediction

Abstract This work presents a method for the analysis of sand-loaded air flow erosion in heritage sites by means of Computational Fluid Dynamics (CFD). This is intended for cases where particle loaded air flow represents a significant contribution to the erosion process. An investigation of the wind erosion over the heritage site of Baelo Claudia, near Tarifa in Spain, is developed in order to present the method. The site is located directly on the beach by the Mediterranean Sea, on one of the windiest locations in South Europe. The presence of large amounts of sand from the beach in such a windy area is making the site extremely prone to suffer from erosion, as evidenced by the present state of one of the most well-known items in the site, the “Cardo of the Columns”. In this study, a CFD model of the “Cardo of the Columns” area, including the terrain features has been developed. The wind has been modelled according to the statistics available of wind velocity and direction for the site, and sand particles have been included in the simulation by means of the Lagrangian Particle Tracking model. The effect of the sand particles over the columns has been modelled with the erosion model from Finnie. Based on simple in situ measurements and assumptions, an erosion rate of 3.55 kg/year has been calculated, which represents a 30% of the total initial mass of the columns. The constants of the CFD erosion model have been calibrated so that results match the theoretical predictions of the erosion rate. In addition, the erosion-caused damage prediction is predicted for evaluating the state of the columns in the next 50 and 100 years, and potential remedial measures such as the installation of wind baffle are evaluated with the aid of the CFD model.