Crossover between lifting surfaces and its similarity to gust interaction response

Multi-body interactions, especially the crossover between two lifting bodies, are common in different aerial vehicles and vertical-axis wind turbine applications. These interactions add periodic excursions to the loads, leading to vibrations and altering the system's acoustic signatures. A fundamental study of the crossover phenomena is required to understand its implications on operating systems. While fundamental studies have not been conducted to understand its impact, it shares some similarities with other fundamental unsteady problems, such as gust interactions. During the crossover between two lifting bodies, the induced transverse gust from one lifting surface could dictate the load response of the other. The focus of this study is to explore the similarities between the crossover and gust interaction problems at different operating conditions. We also explore the applicability of using unsteady linear theories to model the load response during the crossover. Experimental measures have been applied to conduct these studies in a hydrodynamic towing tank facility. Here, two wings were translated in opposite directions, leading to a single crossover event, and loads and flowfield were measured. The results show that the linear gust interaction models predict some aspects of the interactions during the crossover. The predictions from the linear models fail during phases when the lifting surfaces align and modify the flow features.