@Article{DoniniCrisFach:2020:GlFlSt,
               author = "Donini, Mariovane S. and Cristaldo, Cesar Flaubiano da Cruz and 
                         Fachini Filho, Fernando",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and 
                         {Universidade Federal do Pampa (UNIPAMPA)} and {Instituto Nacional 
                         de Pesquisas Espaciais (INPE)}",
                title = "Buoyant Tsuji diffusion flames: global flame structure and flow 
                         field",
              journal = "Journal of Fluid Mechanics",
                 year = "2020",
               volume = "895",
                pages = "A17",
                month = "July",
             keywords = "laminar reacting flows, buoyancy-driven instability, vortex 
                         dynamics.",
             abstract = "The present work analyses how buoyancy is impacting the topology 
                         of diffusion flames established around a horizontal cylindrical 
                         burner. The flow conditions are chosen such that the system is 
                         subjected to negative and positive buoyant forces. It is proposed 
                         in this study to investigate the effect of a modulation of the 
                         balance between these buoyant forces on the flame structure by 
                         varying the temperature of the ambient atmosphere. More 
                         specifically, conditions are sought for establishing a buoyant 
                         Tsuji diffusion flame characterized by a very low level of strain 
                         rate in its lower part (i.e. below the burner). To understand the 
                         fundamental mechanisms controlling the whole flame topology, a 
                         model is proposed which assumes steadiness and incompressibility 
                         of the flow while retaining buoyancy effects in the momentum 
                         balance. The results showed that an increase of the ambient 
                         temperature leads to the appearance of a counterflow zone below 
                         the burner where the flame is undergoing very low levels of strain 
                         rate. The overall flame proves to be shorter than its counterpart 
                         observed in the forced convection regime. In addition, it is shown 
                         that an order of magnitude analysis is able to recover the 
                         sensitivity of the flame behaviour to the Peclet and Froude 
                         numbers as well as to the combustion parameters. In a certain 
                         range of the ambient-atmosphere temperature, the flow field 
                         changes dramatically: for the same boundary conditions, there are 
                         two steady-state solutions which depend on the initial conditions, 
                         i.e. the system presents a hysteresis.",
                  doi = "10.1017/jfm.2020.266",
                  url = "http://dx.doi.org/10.1017/jfm.2020.266",
                 issn = "0022-1120",
             language = "en",
           targetfile = "donini_buoyant.pdf",
        urlaccessdate = "27 abr. 2024"
}