关键词: 粗糙度, 空气动力粗糙度, 下垫面粗糙度, 直立植物

Abstract: The roughness properties of standing vegetation and their influential factors were studied in wind tunnel by using artificial plant models.It was found that with any wind velocity the roughness factor(Z₀) in the log-law wind profile increased with the vegetation density by power function,the exponent <1;and decreased with wind velocity by some kind of exponential function.The predicted Z₀ values by the multivariate model including wind velocity and vegetation density based on experiment data matched those measured reasonably well.Therefore,the Z₀ in the log law is a physical dimension reflecting the interaction of the near-surface airflow and surface conditions,correcting the common view that Z₀ is only determined by the surface conditions.It is suggested that cautions should be taken in applying the concepts of aerodynamic roughness and surface roughness.

Key words: roughness, aerodynamic roughness, surface roughness, standing vegetation