### Resumé

Originalsprog | Engelsk |
---|---|

Artikelnummer | 052143 |

Tidsskrift | Physical Review E (Statistical, Nonlinear, and Soft Matter Physics) |

Vol/bind | 88 |

Udgave nummer | 5 |

ISSN | 1539-3755 |

DOI | |

Status | Udgivet - 27 nov. 2013 |

### Citer dette

*Physical Review E (Statistical, Nonlinear, and Soft Matter Physics)*,

*88*(5), [052143]. https://doi.org/10.1103/PhysRevE.88.052143

}

*Physical Review E (Statistical, Nonlinear, and Soft Matter Physics)*, bind 88, nr. 5, 052143. https://doi.org/10.1103/PhysRevE.88.052143

**Effects of nanoscale density inhomogeneities on shearing fluids.** / Ben, Dalton,; Peter, Daivis,; Hansen, Jesper Schmidt; Todd, Billy.

Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › peer review

TY - JOUR

T1 - Effects of nanoscale density inhomogeneities on shearing fluids

AU - Ben, Dalton,

AU - Peter, Daivis,

AU - Hansen, Jesper Schmidt

AU - Todd, Billy

PY - 2013/11/27

Y1 - 2013/11/27

N2 - It is well known that density inhomogeneities at the solid-liquid interface can have a strong effect on the velocity profile of a nanoconfined fluid in planar Poiseuille flow. However, it is difficult to control the density inhomogeneities induced by solid walls, making this type of system unsuitable for a comprehensive study of the effect on density inhomogeneity on nanofluidic flow. In this paper, we employ an external force compatible with periodic boundary conditions to induce the density variation, which greatly simplifies the problem when compared to flow in nonperiodic nanoconfined systems. Using the sinusoidal transverse force method to produce shearing velocity profiles and the sinusoidal longitudinal force method to produce inhomogeneous density profiles, we are able to observe the interactions between the two property inhomogeneities at the level of individual Fourier components. This gives us a method for direct measurement of the coupling between the density and velocity fields and allows us to introduce various feedback control mechanisms which customize fluid behavior in individual Fourier components. We briefly discuss the role of temperature inhomogeneity and consider whether local thermal expansion due to nonuniform viscous heating is sufficient to account for shear-induced density inhomogeneities. We also consider the local Newtonian constitutive relation relating the shear stress to the velocity gradient and show that the local model breaks down for sufficiently large density inhomogeneities over atomic length scales.

AB - It is well known that density inhomogeneities at the solid-liquid interface can have a strong effect on the velocity profile of a nanoconfined fluid in planar Poiseuille flow. However, it is difficult to control the density inhomogeneities induced by solid walls, making this type of system unsuitable for a comprehensive study of the effect on density inhomogeneity on nanofluidic flow. In this paper, we employ an external force compatible with periodic boundary conditions to induce the density variation, which greatly simplifies the problem when compared to flow in nonperiodic nanoconfined systems. Using the sinusoidal transverse force method to produce shearing velocity profiles and the sinusoidal longitudinal force method to produce inhomogeneous density profiles, we are able to observe the interactions between the two property inhomogeneities at the level of individual Fourier components. This gives us a method for direct measurement of the coupling between the density and velocity fields and allows us to introduce various feedback control mechanisms which customize fluid behavior in individual Fourier components. We briefly discuss the role of temperature inhomogeneity and consider whether local thermal expansion due to nonuniform viscous heating is sufficient to account for shear-induced density inhomogeneities. We also consider the local Newtonian constitutive relation relating the shear stress to the velocity gradient and show that the local model breaks down for sufficiently large density inhomogeneities over atomic length scales.

U2 - 10.1103/PhysRevE.88.052143

DO - 10.1103/PhysRevE.88.052143

M3 - Journal article

VL - 88

JO - Physical Review E

JF - Physical Review E

SN - 2470-0045

IS - 5

M1 - 052143

ER -