Since microfabrication techniques are typically planar processes, microchannel flows typically have significant predevelopment due to the upstream reservoir having the same height as the microchannel. The main concerns of the current study are categorized into finding the effects of typical microchannel geometry on the velocity entrance length in the laminar flow regime and providing the turbul...

In this paper, an attempt has been made to predict and evaluate the entrance length in pipe for low Reynolds number flow using evolutionary-optimized Adaptive-Neuro Fuzzy Inference System (ANFIS). For optimization purpose, evolutionary algorithm namely particle swarm optimization (PSO) is adopted. We trained and tested the model using 100 experimental records from computational fluid dynamics (...

The preceding chapter discussed the microscopic, kinetic and two-fluid decsriptions of a plasma. But we would actually like a simpler model — one that would include most of the macroscopic properties of a plasma in a “one-fluid” model. The simplest such model is magnetohydrodynamics (MHD), which is a combination of a one-fluid (hydrodynamic-type plus Lorentz force effects) model for the plasma ...

The dissipative nature of heat transfer relaxes thermal flows to an equilibrium state that is devoid temperature gradients. distance reach – the entrance length a consequence diffusion and mixing by convection. presence particles can modify due interphase turbulence modulation momentum coupling. In this work, Eulerian–Lagrangian simulations are utilized probe effect solids heterogeneity (e.g., ...

Water transport through aquaporin water channels occurs extensively in cell membranes. Hourglass-shaped (biconical) pores resemble the geometry of these aquaporin channels and therefore attract much research attention. We assumed that hourglass-shaped nanopores are capable of high water permeation like biological aquaporins. In order to prove the assumption, we investigated nanoscale water tran...

Heat transfer in the thermal entrance region of trapezoidal microchannels is investigated for hydrodynamically fully developed, single-phase, laminar flow with no-slip conditions. Three-dimensional numerical simulations were performed using a finite-volume approach for trapezoidal channels with a wide range of aspect ratios. The sidewall angles of 54.7 and 45 are chosen to correspond to etch-re...

Membrane rejection models generally neglect the effect of the pore entrance on intrapore particle transport. However, entrance effects are expected to be particularly important with ultrathin membranes, where membrane thickness is typically comparable to pore size. In this work, a 2D model was developed to simulate particle motion for spherical particles moving at small Re and infinite Pe from ...

In studying the fluid flow and heat transfer in microchannels, various claims have been made regarding transition at Reynolds numbers significantly below 2300. As a first step in identifying the reasons for such early transition, the effect of entrance geometry on the pressure drop and transition to turbulence is studied experimentally in a conventional channel of 1.9 cm inner diameter. Four ty...

was demonstrated in five patients by using programmed atrial stimulation and His bundle recordings. Entrance block into the A-V node occurred in a narrow range (28-33%) of the basic cycle length and concealed conduction occurred at coupling intervals longer than this range. It appears that entrance block of these early APBs is due to a "functional block" between the atrium and the A-V node. The...

PURPOSE The object of this study was to evaluate entrance angle effects on femoral tunnel length and cartilage damage during anteromedial portal drilling using three-dimensional computer simulation. MATERIALS AND METHODS Data was obtained from an anatomic study performed using 16 cadaveric knees. The anterior cruciate ligament femoral insertion was dissected and the knees were scanned by comp...