Simulation of depth-integrated flow over a hill

This paper details work conducted using the commercial CFD software package ANSYS Fluent to investigate the depth-integrated flow over a hill. The calculation of wake development is really important for the design of the layout and the operation of a wind farm. Simulating a wind farm with more than one fully detailed wind turbines and possibly complex terrain geometry requires significant computational power and time. For this reason the depth-integrated flow equations derived by integrating the original 3D flow equations over the depth are presented. The complex 3D geometry need not be modelled or discretized in the pre-processing state: instead, the geometry of the terrain is only described with source terms in the depth-integrated equations, which are then solved in a very simple and fixed 2D domain. This approach reduces the equations from 3D to 2D and decreases the elapsed time of CFD simulations from hours to minutes. Thus, it is very practicable modelling method in real time optimization work. 2D CFD simulations of flow over a hill with depth-integrated governing equations are compared with full 3D models. The depth-integrated model will be used in future to find the optimal position of wind turbines in the wind park.