粗糙元几何参数的交互作用对床面空气动力学粗糙度的影响

 为了全面地揭示粗糙元的所有几何参数的交互作用对空气动力学粗糙度的影响,利用风洞实验研究了粗糙元高度、密度、高度与间距比、孔隙度和方向比率等几何参数交互作用对空气动力学粗糙度的影响。结果表明,密实和孔隙粗糙元的无量纲空气动力学粗糙度（空气动力学粗糙度度/粗糙元高度）均可表示为粗糙元密度/等效密度的正比例函数,而比例系数反映了粗糙元几何参数交互作用。据此,该研究发展了一个全面反映粗糙元高度h、密度/等效密度λ、高度与行间距比Sp和方向比率AR等几何参数交互作用的空气动力学粗糙度模式:Z0h=-0.0028+0.5403S0.32p·AR-0.07·λ。该模式改进了模拟的精度,扩大了适用范围。

The Integrated Effects of Roughness Elements' Geometric Parameters on Aerodynamic Roughness Length

Aerodynamic roughness lengths over surfaces were investigated by a wind tunnel experiment so as to understand integrated effects of roughness elements’ height, density, spacing, porous index and aspect ratios on aerodynamic roughness length. Results indicate that normalized aerodynamic roughness lengths (ratio of aerodynamic roughness length to roughness element height) over compact and porous roughness elements are direct proportional to roughness elements densities, and the proportionality coefficient is a quantitative reflection of the integrated effects of roughness elements’ geometric parameters on roughness lengths. A multiple variant model of aerodynamic roughness is proposed on basis of the integrated effect of geometric parameters (roughness element height h, roughness element density λ, ratio of spacing between two adjacent individual roughness elements to height Sp, and aspect ratio of individual roughness elements AR) on aerodynamic roughness length: Z0h=-0.0028+0.5403S0.32p·AR-0.07·λ.  This new model improves significantly simulation accuracy and expands application scope of some previous models.