A numerical study of the wake behind a blunt-trailing-edged body. Part 2: The topology of the flow Marcos A. Ortega 1, ∗, †, ‡ , Roberto M. Girardi 1 and Jorge H. Silvestrini 2 1 ITA—Tech. Institute of Aeronautics, Division of Aeronautical Engineering, S. J. Campos, Brazil 2 PUC/RS—Pontifical Catholic University, School of Engineering, Porto Alegre, Brazil SUMMARY This project focuses on the wake behind a two-dimensional blunt-trailing-edged body. The body has an elliptical nose followed by a straight section that ends in a blunt base. For this geometry, the boundary layer separation points are defined and fixed. This permits a better assessment of the vital influence of the boundary layers upon the wake. It is hoped that the study of this special geometry will contribute to a better understanding of the wake flow. The main aim of this article is to study the topology of the wake by means of direct numerical simulation (DNS). The idea is to mimic some experimental work techniques. In an experiment, by means of proper synchronization, one is able to arrive at the mean-in-the-phase fields. In the present work, similar data are obtained through the use of numerical tools. The topology of the wake flow in terms of the movement of the coherent structures, fields of Reynolds stresses, position of saddles and centers, is obtained for certain values of the body’s aspect ratio. A comparison with the circular cylinder experimental data is also provided. An important result is the finding of some specific stress distributions around the main structures. The stress level lines are a hint of where the energy transfer of the mean flow to the turbulence is more intense. Copyright  2011 John Wiley & Sons, Ltd. Received 5 January 2010; Revised 12 July 2010; Accepted 5 December 2010 KEY WORDS: wake topology; elongated cylinder; numerical analysis; mean in the phase; coherent structures; stress distributions; centers and saddle points 1. INTRODUCTION In a first paper by the same authors [1], the very important issue of the elongated cylinder’s onset of shedding as a function of the aspect ratio (AR) was discussed. On that occasion we gave a summarized retrospect of the many works dealing with the physics of blunt body wakes, with the basic aim of positioning the present work. Most of the literature publications can be grossly divided between stability and topological studies. The present article can be included in the latter category. The amount of publications dealing with the topology of blunt body wakes is enormous. Some works are outstanding, as for example the experimental studies of Roshko [2] and Reynolds and Hussain [3]. The elongated cylinder was experimentally investigated by Bearman [4–6] in the sixties of the last century. His work focused mainly on mean parameters and topology details for the body with and without splitter plates. The numerical analysis of Braza et al. [7] for the flow about the circular cylinder is very instructive and quite complete. The authors discuss in ∗ Correspondence to: Marcos A. Ortega, ITA, Techonological Institute of Aeronautics, São José dos Campos, SP, 12228-900, Brazil. † E-mail: ortega@ita.br ‡ AIAA Senior Member. Copyright  2011 John Wiley & Sons, Ltd. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS Int. J. Numer. Meth. Fluids Published online 31 January 2011 in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/fld.2533 2012; 69:29–56