Study on the characteristics of aeolian sand movement and accumulation at the east wall of Suoyang Ancient City based on CFD

Abstract

The frequent eolian processes in the northwest region of China pose a persistent threat to the conservation of earthen sites. Located in the “World Wind City” of Guazhou, Suoyang Ancient City experiences maximum wind velocities of 24 m/s, leading to severe sand accumulation and damage to its walls. This study focused on a typical 70-m-long section of the east wall of Suoyang Ancient City, featuring a gap, and utilized unmanned aerial vehicle (UAV)-assisted modeling technology to construct a three-dimensional model of the wall. Computational fluid dynamics (CFD) methods were employed to simulate the movement and accumulation processes of wind-blown sand. The research found that upward airflow at the upper part of the wall enables sand particles to surmount the wall's top, while downward airflow at the lower part accelerates the downward deposition of sand particles at the base of the wall. The wind field on the windward side is evenly distributed, resulting in relatively uniform sand deposition. Conversely, on the leeward side, a reflux zone forms after the airflow passes over the wall, causing sand particles to accumulate in an arc-shaped pattern behind the wall. The simulated results align with actual observations of sand accumulation at the gap in the east wall, providing valuable insights for sand prevention and control efforts at the Suoyang Ancient City.

Graphical Abstract