caa a22 4500 605466912 CHVBK 20210128100309.0 cr unu---uuuuu 210128e20151001xx s 000 0 eng 10.1007/s00397-015-0875-6 doi (NATIONALLICENCE)springer-10.1007/s00397-015-0875-6 Mechanisms of onset for moderate Mach number instabilities of viscoelastic flows around confined cylinders [Elektronische Daten] [Xueda Shi, Stephen Kenney, Ganesh Chapagain, Gordon Christopher] An examination of the upstream and downstream instabilities that occur for highly confined and bounded viscoelastic flows around a cylinder is presented. An elasticity number-Mach number (El-Ma) phase space is used to demonstrate that the onset of downstream instabilities at Ma = 1; these instabilities are instigated by the disturbance of the base flow by traveling elastic waves. After the onset of the downstream instability, an upstream instability eventually occurs for Ma crit ~ 10; however, this number is affected by both channel geometry and fluid properties. The upstream instability is instigated by perturbations of the flow field caused by the downstream instability and does not occur until a critical perturbation size at a given velocity is exceeded. The effects of these flow regimes on flow resistance are characterized by examining excess pressure drop; a significant increase in flow resistance is observed at the onset of the upstream instability. Springer-Verlag Berlin Heidelberg, 2015 Instability nationallicence Viscoelastic fluid nationallicence Boger fluid nationallicence Shi Xueda Department of Mechanical Engineering, Texas Tech University, 79409, Lubbock, TX, USA aut Kenney Stephen Department of Mechanical Engineering, Texas Tech University, 79409, Lubbock, TX, USA aut Chapagain Ganesh Department of Mechanical Engineering, Texas Tech University, 79409, Lubbock, TX, USA aut Christopher Gordon Department of Mechanical Engineering, Texas Tech University, 79409, Lubbock, TX, USA aut Rheologica Acta Springer Berlin Heidelberg 54/9-10(2015-10-01), 805-815 0035-4511 54:9-10<805 2015 54 397 https://doi.org/10.1007/s00397-015-0875-6 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00397-015-0875-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Shi Xueda Department of Mechanical Engineering, Texas Tech University, 79409, Lubbock, TX, USA aut NATIONALLICENCE 700 1- Kenney Stephen Department of Mechanical Engineering, Texas Tech University, 79409, Lubbock, TX, USA aut NATIONALLICENCE 700 1- Chapagain Ganesh Department of Mechanical Engineering, Texas Tech University, 79409, Lubbock, TX, USA aut NATIONALLICENCE 700 1- Christopher Gordon Department of Mechanical Engineering, Texas Tech University, 79409, Lubbock, TX, USA aut NATIONALLICENCE 773 0- Rheologica Acta Springer Berlin Heidelberg 54/9-10(2015-10-01), 805-815 0035-4511 54:9-10<805 2015 54 397