Inter-Comparison of Neutral Atmospheric Boundary Layer Flows Using Different Numerical Models

Abstract

Due to increasing demands for wind energy applications the investigations of wind data in atmospheric boundary layer have become essential In this study the flow data were computed from different numerical approaches The approaches include the commercial package ANSYS Fluent and the pseudo-spectrum in-house code The LES (Large-Eddy Simulation) turbulence closures were applied in our atmospheric boundary layer simulations LES is a powerful tool to simulate atmospheric turbulence It contains the advantages that all of the components are solved in flow field but only the small scales require modeling LES is available to predict instantaneous turbulent behavior in turbulent flows In brief the principle idea behind LES is to reduce computational cost and improve accuracy and authenticity in the turbulent flows There are two different wall boundary conditions used in the Fluent simulations: (a) stationary wall with no shear condition and (b) specified shear stresses based on Monin-Obukhov similarity theory which carried out two different roughness lengths In the near-surface region the streamwise velocity and velocity variance results obtained from the Fluent were underestimated but the velocity spectra yielded a reliable agreement with theory Compared to the results obtained from the Fluent the in-house code based on the pseudo-spectrum method showed better agreement with the theory in all turbulence statistics

Date of Award	2018 Aug 9
Original language	English
Supervisor	Yu-Ting Wu (Supervisor)