Study of the origin of unsteadiness in unforced three-dimensional laminar separation bubbles

• Grant number: 14/24782-0
• Support Opportunities: Regular Research Grants
• Start date: March 01, 2015
• End date: February 28, 2017
• Field of knowledge: Engineering - Aerospace Engineering - Aerodynamics
• Principal Investigator: Elmer Mateus Gennaro
• Grantee: Elmer Mateus Gennaro
• Host Institution: Universidade Estadual Paulista (UNESP). Campus Experimental São João da Boa Vista. São João da Boa Vista , SP, Brazil
• Associated researchers: Daniel Rodríguez Álvarez

Abstract

The project proposes the study unsteadiness in unforced three-dimensional laminar separation bubbles, which is very important in aeronautical applications. The laminar separation bubbles also have great importance for the effects they generate of pitch and roll momentum. The study may contribute to the open issues and the improvement of forecasting methods the transition point, an important topic in aircraft design. This contribution is also directly related to reduced drag. The issue will be addressed within the scope of the global linear stability theory. Linear instability analyzes based on eigenvalue problem solving may be limited depending on the assumptions made for the base flow, and therefore has a huge computational cost. In this regard, the dimensionality of the bifurcated separation bubble makes it necessary to introduce a three-dimensional eigenvalue problem for the analysis of secondary instability. In this project, we propose a unique and innovative methodology for the analysis of three-dimensional flow in the streamwise direction that variations occur on a scale that is large compared with the variations in the cross-flow sections. Reducing the size of the problem from a three-dimensional eigenvalue problem for the various problems of two-dimensional eigenvalues implies into an approach that allows the analysis of three-dimensional instability of laminar separation bubbles at an affordable computational cost. Expected to contribute to the understanding of the mechanisms responsible for the origin of unsteadiness in unforced three-dimensional laminar separation bubbles. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

RODRIGUEZ, DANIEL; JOTKAR, MAMTA R.; GENNARO, ELMER M.. Wavepacket models for subsonic twin jets using 3D parabolized stability equations. COMPTES RENDUS MECANIQUE, v. 346, n. 10, p. 890-902, OCT 2018. (14/24782-0, 17/01586-0)

RODRIGUEZ, D.; GENNARO, E. M.. Enhancement of disturbance wave amplification due to the intrinsic three-dimensionalisation of laminar separation bubbles. AERONAUTICAL JOURNAL, v. 123, n. 1268, p. 1492-1507, OCT 2019. (14/24782-0, 17/01586-0)

RODRIGUEZ, DANIEL; GENNARO, ELMER M.; SOUZA, LEANDRO F.. Self-excited primary and secondary instability of laminar separation bubbles. JOURNAL OF FLUID MECHANICS, v. 906, NOV 13 2020. (17/01586-0, 14/24782-0)