Accession Number : AD1016223


Title :   Understanding the Fundamental Roles of Momentum and Vorticity Injections in Flow Control


Descriptive Note : Technical Report,15 May 2013,14 May 2016


Corporate Author : Florida State University Tallahassee, United States


Personal Author(s) : Taira,Kunihiko ; Munday,Phillip ; Nair,Aditya


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/1016223.pdf


Report Date : 02 Sep 2016


Pagination or Media Count : 93


Abstract : The objective of this study is to numerically investigate the fundamental roles that momentum and vorticity injections play in suppressing flow separation over a canonical airfoil. Open-loop control of separated, incompressible flow over a NACA 0012 airfoil at Re = 23,000 is examined through large-eddy simulations. We find that the modification to the flow field can be captured by quantifying both the effects of wall-normal momentum (coefficient of momentum) and wall-normal vorticity (derived coefficient of circulation), by considering a newly defined total input parameter (total coefficient). Moreover, the study has developed advanced analysis techniques. First, the capability to perform bi-global stability analysis has been developed and validated, which can serve as a basis for physics-based active flow control guided by the knowledge of hydrodynamic instabilities. Second, as part of modeling complex unsteady flows in general, efforts in this study have led to the initial development of a novel network-theoretic approach in quantifying nonlinear interactions present in vortical flows.


Descriptors :   Airfoils , Momentum , Open loop systems , Eddies(Fluid mechanics) , Fluid dynamics , Flow fields , Hydrodynamic characteristics


Distribution Statement : APPROVED FOR PUBLIC RELEASE