Influence of rough surfaces on airfoil aerodynamics and the ground effect on near-wall flow

Agricultural aircraft play a pivotal role in crop dusting and aerial applications of fertilizers, pesticides, and herbicides, where their close proximity to crop surfaces during operations has significant implications. These interactions affect not only crop safety and treatment efficacy but also environmental impact and operational optimization. This study investigates the aerodynamic interactions between an airfoil and a rough surface, representing crops, focusing on the dual effects of airfoil proximity on surface flow dynamics and the influence of the rough wall on airfoil aerodynamics. A computational framework employing overset (Chimera) mesh for a movable airfoil is developed and rigorously validated against experimental data. Using this validated model, we examine the aerodynamic consequences of proximity, revealing that the rough wall substantially modifies the flow field around the airfoil, altering lift and drag characteristics. Conversely, the airfoil's motion significantly influences wall shear stress and surface flow patterns on the rough wall. These findings provide new insights into the coupled dynamics of airfoil aerodynamics and wall effects, offering a basis for optimizing agricultural aircraft operations while mitigating environmental and crop impacts.