The pressure distribution on a surface, over which a wall-jet is blowing, is altered by the wall jet's entrainment. It renders the boundary layer approximation – that justifies the use of an inviscid flow solution to determine the pressure over the surface – invalid. Thus, in order for Active Flow Control (AFC) by blowing to become a viable technology, some of the preconceptions associated with Boundary Layer Control (BLC) for many decades must be discarded. In particular, the momentum coefficient used to characterize BLC should be replaced by another variable that represents a conserved quantity that is independent of specific installations. Injected momentum is a vector quantity whose effect on a surface like a wing depends on its specific design, location, and orientation. Therefore, a new approach is proposed based on the AFC system's power consumption and its mass flowrate. Moreover, all flow installations suffer from unavoidable losses, which must be determined in an unambiguous manner, allowing for an impartial comparison of AFC systems. The present article provides examples from tests carried out at various universities and at NASA, exposing some popular misconceptions. It does not provide a design tool due to the complexity of the needed approach, but a method to assess the efficacy and efficiency of an evolving platform that includes AFC is suggested.

中文翻译：

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需要重新评估主动流量控制的设计工具


壁射流吹过的表面上的压力分布会因壁射流的夹带而改变。它使得边界层近似（证明使用无粘流解决方案来确定表面压力的合理性）无效。因此，为了使吹气主动流量控制 (AFC) 成为一项可行的技术，必须放弃几十年来与边界层控制 (BLC) 相关的一些先入之见。特别是，用于表征 BLC 的动量系数应替换为另一个代表独立于特定安装的守恒量的变量。注入动量是一个矢量，其对机翼等表面的影响取决于其具体设计、位置和方向。因此，提出了一种基于AFC系统功耗和质量流量的新方法。此外，所有流量装置都会遭受不可避免的损失，必须以明确的方式确定损失，以便对 AFC 系统进行公正的比较。本文提供了在各大学和美国宇航局进行的测试的例子，揭露了一些流行的误解。由于所需方法的复杂性，它没有提供设计工具，但建议使用一种方法来评估包括 AFC 在内的不断发展的平台的功效和效率。