Numerical Simulation of Airflow Field over a Pyramid Dune
In this paper, the airflow field of a pyramid dune, which is located at the eastern edge of the Mingsha Mountain atop the famous Mogao Grottoes, was simulated by numerical simulation. Changes of pressure field and velocity field over the dune surface under multidirectional wind regime were analyzed. A 3-dimensional numerical model in equal proportion to the real dune was built with the help of ground stereo photogrammetry. The variances of three prevailing wind directions that cannot be expressed by previous 2dimension models were obtained. Unstructured grid method was used to adjust to the highly irregular terrain of the pyramid dune. In our computational fluid dynamics simulations, the so-called shear-stress transportmodel was applied and the results were compared with previous wind tunnel measurement and numerical simulation works. It indicates that this 3-dimensional model can successfully predict the information of the whole airflow field, including the stagnation zone at the toe, the accelerating region up the stoss slope, the recirculation region in the lee, the wind velocity and pressure distribution patterns and so on. Besides, the flow-dune form interaction is expressed more comprehensively. Velocity pattern is directly related to the pressure distribution in the flow field.
NETL
NSTL
万方数据
维普
