RT Journal Article
ID 4c8e7e922279565b
A1 Tsukahara, Takahiro
A1 Kawase, T. 
A1 Kawaguchi, Yasuo
T1 HEAT TRANSFER IN A VISCOELASTIC ORIFICE FLOW AT LOW TO MODERATE REYNOLDS NUMBERS
JF Computational Thermal Sciences: An International Journal
JO CTS
YR 2014
FD 2014-02-20
VO 6
IS 1
SP 79
OP 90
K1 direct numerical simulation
K1 drag reduction
K1 Giesekus model
K1 heat transfer
K1 non-Newtonian fluid
K1 orifice
K1 Toms effect
K1 turbulence
K1 viscoelasticity
AB Direct numerical simulations of heat transfer in channel flows of a viscoelastic fluid with an immersed periodic rectangular orifice were carried out to investigate the statistics of the velocity and thermal fields. The friction Weissenberg number of the viscoelastic fluid was set at 20 and the Prandtl number was given as either 1.0 or 2.0. In the present flow configuration, the reduction rates of the drag factor and the Nusselt number were ranged in the percent drag reduction DR% = −90%−20% and the percent heat-transfer reduction HTR% = 0%−50%, respectively. The variations observed in the Reynolds-number dependencies of DR%, HTR%, and the separated flow behind the orifice were analyzed. Consequently, the viscoelasticity was found to affect the orifice flow and its heat transfer most significantly in the transitional regime, since it suppressed the turbulent transition and/or the Kelvin-Helmholtz instability of the separated shear layer emanating from the orifice edge.
PB Begell House
LK https://www.dl.begellhouse.com/journals/648192910890cd0e,30dacead1cf54adf,4c8e7e922279565b.html