Direct numerical simulation of elastic turbulence and its mixing-enhancement effect in a straight channel flow

Abstract

Direct numerical simulation of elastic turbulence and its mixing-enhancement effect in a straight channel flow * Zhang Hong-Na(张红娜) a)b) , Li Feng-Chen(李凤臣) a) † , Cao Yang(曹 阳) a) , Kunugi Tomoaki a)b) , and Yu Bo(宇 波) c)

Elastic turbulence influences and convective heat transfer within a miniature viscous disk pump

“…Associated velocity boundary conditions are then given by (12) The resulting velocity profile is then of the form (13) Again considering Eqn. (10), this equation is now re-arranged by employing a nondimensional temperature, which is given by the following equation (14) Here, t m is the mixed-mean temperature and t 0 is the wall temperature. In addition, ( Fig.…”

“…For turbulent and laminar flows, such viscoelastic fluids show high heat transfer coefficients which are due to secondary motions, which are tied to unequal normal stresses within the viscoelastic fluids. Numerical investigations are described by Zhang et al [9,10] which address connections between elastic turbulence and enhancement of local flow mixing. Abed et al [11], and Whalley et al [12] describe enhancements in flow mixing from elastic turbulence which often result in enhancements of convective heat transfer rates, when compared for the same configuration and same experimental conditions.…”

Elastically induced turbulence in Taylor–Couette flow: direct numerical simulation and mechanistic insight

“…Although numerical simulation of an elastically driven flow transition from a stationary to randomly fluctuating states at vanishing Re and O(1) We, has been recently performed, the computations are confined to two-dimensional or threedimensional periodic Kolmogorov flows excited by an external forcing (Berti et al 2008;Berti & Boffetta 2010;Zhang et al 2013). Hence, the detailed flow-microstructure coupling needed for elucidating the mechanism of 'elastically Elastically induced turbulence in Taylor-Couette flow induced turbulence' is still lacking.…”

Probing nonlinear rheology layer-by-layer in interfacial hydration water

“…Although shear thinning (decrease of viscosity) originates from the decrease of particle density correlation (2,12), shear thickening (4,7,8,(13)(14)(15)(16)(17) (increase of viscosity) has been understood in various perspectives such as hydrodynamic instability (18) at high Reynolds number (Re) or order-disorder transition (13,14) at low Re and high Weissenberg number (Wi) [a measure of elasticity of viscoelastic flows (1); see SI Appendix, section S1, for nonlinear hydrodynamics formalism based on Re and Wi]. In particular, such a viscoelastic flow with low Re and high Wi exhibits behaviors similar to the inertial turbulence of Newtonian flow, so termed the elastic turbulence (4,17). Despite extensive studies, however, one still lacks understanding of (i) the role of elastic instability in the enhanced flow resistance and (ii) the unexplored characteristics of nonlinear rheology at nanoscale.…”