variavel0=<b>Francisco Marcondes</b> - marconde@dem.ufc.br Universidade Federal do Ceará
<b>Vinicius de Souza Melo</b> - vinisouzamelo@bol.com.br Universidade Federal da Paraíba
<b>José Mauricio Gurgel</b> - gurgel@les.ufpb.br 
<b>Abstract.</b> Natural convection in open-ended channels has been extensively studied in several applications such as in the cooling of electronic equipments, solar collectors, among others. Most studies have considered the natural convection in vertical parallel channels. Moreover, most ones neglect the diffusion terms in the streamwise direction, so a march procedure may be employed. However if a flow reversal occurs it may not be possible to neglect the diffusion of momentum and energy equations in any direction. In the present work the natural convection in open-ended parallel, convergent and divergent channels is analyzed retaining all diffusion terms in the conservation equations. The equations are solved by the finite-volume method using a co-located variable arrangement. The results are present in terms of velocity vectors, streamlines, isotherms, local and average Nusselt number.
<b>Keywords.</b> Natural convection, Open-ended parallel, convergent and divergent channels, Finite Volume method, collocated arrangement.