Knudsen number
Analysis of the thermomechanical inconsistency of some extended hydrodynamic models at high Knudsen number
... with τ the microscopic and t the macroscopic time scales; ε may also be viewed as a Knudsen number as it is the ratio of molecular to macroscopic relaxation times. In flows with speeds typically of the same ...
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Calculation of Friction Coefficient and Analysis of Fluid Flow in a Stepped Micro-Channel for Wide Range of Knudsen Number Using Lattice Boltzmann (MRT) Method
... large number of discrete velocities are not numerically ...Kn number in slip flow ...of Knudsen number in slip and transition flow ...of Knudsen numbers that shows the regimes of flows ...
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A kinetic theory description for external spherical flows with arbitrary Knudsen number by a moment method
... Lees suggested that the distribution function in the Maxwell integral equation of transfer b e represented by a weighting function expressed in terms of a number of parametric functions [r] ...
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Modelling thermally induced non-equilibrium gas flows by coupling kinetic and extended thermodynamic methods
... In terms of the system entropy, it is very interesting to note that, unlike the other flow properties, the distributions of entropies are totally different between the lower and higher Knudsen numbers. We have ...
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Numerical investigating the gas slip flow in the microchannel heat sink using different materials
... Nusselt number in the slip flow regime is smaller than no slip flow ...Nusselt number, while the temperature-jump tends to decrease it, and the combined effect could result in an increase or a decrease in ...
7
Non-equilibrium dynamics of dense gas under tight confinement
... (the Knudsen number, Kn) becomes appreciable in narrow channels, the Boltzmann equation is commonly used to describe the collective motion of a dilute gas from the hydrodynamic to the free-molecular flow ...
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Capturing Knudsen layer phenomena using lattice Boltzmann model
... encountered in micro- and nano-scale systems typically involve low Mach numbers and low Knudsen numbers. Under these conditions, the DSMC approach is not computationally efficient due to the requirement to perform ...
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Nonequilibrium dynamics of dense gas under tight confinement
... When the collisions between the hard discs are inelastic, we found that the MFR increases as the restitution coefficient decreases due to the increase of the velocity slip and the decrease of the effective Knudsen ...
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Air entrainment in dynamic wetting : Knudsen effects and the influence of ambient air pressure
... Recent experiments on coating flows and liquid drop impact both demonstrate that wetting failures caused by air entrainment can be suppressed by reducing the ambient gas pressure. Here, it is shown that non-equilibrium ...
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A wall-function approach to incorporating Knudsen-layer effects in gas micro flow simulations
... the Knudsen number is defined as the ratio of the mean free path to half the channel height ...the Knudsen-layer wall function approach produces better agreement with the DSMC data than do ...
7
Size-dependent Vibration and Instability of Magneto-electro-elastic Nano-scale Pipes Containing an Internal Flow with Slip Boundary Condition
... Assuming nonzero value for Kn (known as Knudsen number), one can model the interacting fluid flow as slip flow. The effect of Kn on eigenvalue diagram in this system is shown in Figure 4, for doubly-clamped ...
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Evaporation driven vapour micro flows : analytical solutions from moment methods
... The general interest of the present study is to explore boundary-value problems for moderately rarefied gas flows, with an emphasis on evaporation from nanostructures. For example, evaporative cooling from nano pores ∼ O ...
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Thermophoresis of a spherical particle : modelling through moment based, macroscopic transport equations
... Employing the closed-form expressions for the field variables in the gas obtained here, we plotted their profiles in a neighbourhood of the sphere alongside predictions from a model Boltzmann equation from the ...
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Coupled constitutive relations : a second law based higher order closure for hydrodynamics
... The development of macroscopic transport equations for rarefied gases at larger orders in the Knudsen number with a full formulation of the second law of thermodynamics is an im- portant project within the ...
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Lattice Boltzmann modelling Knudsen layer effect in non-equilibrium flows
... the Knudsen number (Kn), defined as the ratio of the gas molecular mean free path λ to the device characteristic length ...The Knudsen layer is the local non-equilibrium region extending several mean ...
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Computing the near-wall region in gas micro- and nanofluidics : critical Knudsen layer phenomena
... In the region close to a surface (within a few λ) the flow is highly non-equilibrial and the relationship between stress and strain is non-linear. This region is known as the Knudsen layer. Evidently, the linear ...
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Computing the near-wall region in gas micro- and nanofluidics : critical Knudsen layer phenomena
... In the region close to a surface (within a few λ) the flow is highly non-equilibrial and the relationship between stress and strain is non-linear. This region is known as the Knudsen layer. Evidently, the linear ...
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A Review On Enhancement Of Heat Transfer In Microchannel Heat Exchanger
... In this review paper we have covered the factor affecting heat transfer in microchannel. We have discussed slip flow concept, Knudsen number, effect of channel geometry, problem of frosting, nanofluids and ...
7
Modeling of Knudsen layer effects in micro/nanoscale gas flows
... non-dimensional Knudsen number, Kn, defined as the ratio of the molecular mean free path (MFP) of the gas, λ, to a characteristic flow field dimension, indicates the flows are often ...a Knudsen ...
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Artificial ionospheric layers driven by high-frequency radiowaves : an assessment
... Journal of Geophysical Research: Space Physics Ein EB FAI FM F0 = FM + Fs Fs Ft u Ct IAPD IL and PL Knudsen number L and UH LH and S Lo MI MUIR NC OTSI OTSIuh Lo PDOL PDOuh∕eb the input [r] ...
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