Poiseuille number behavior in an adiabatically choked microchannel in the slip regime

2020 ◽  
Vol 32 (11) ◽  
pp. 112002
Author(s):  
Richie Garg ◽  
Amit Agrawal
Keyword(s):  
Slip Regime ◽  
Poiseuille Number

scholarly journals Triggering avalanches by transverse perturbations in a rotating drum

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Vicente Salinas ◽  
Cristóbal Quiñinao ◽  
Sebastián González ◽  
Gustavo Castillo
Keyword(s):  
Hopf Bifurcation ◽  
Theoretical Model ◽  
Order Parameter ◽  
Small Scale ◽  
Rotating Drum ◽  
Governing Parameter ◽  
Stick Slip ◽  
Slip Regime ◽  
Axis Of Rotation

AbstractWe study the role of small-scale perturbations in the onset of avalanches in a rotating drum in the stick-slip regime. By vibrating the system along the axis of rotation with an amplitude orders of magnitude smaller than the particles’ diameter, we found that the order parameter that properly describes the system is the kinetic energy. We also show that, for high enough frequencies, the onset of the avalanche is determined by the amplitude of the oscillation, contrary to previous studies that showed that either acceleration or velocity was the governing parameter. Finally, we present a theoretical model that explains the transition between the continuous and discrete avalanche regimes as a supercritical Hopf bifurcation.

GRANULAR FAILURE: THE ORIGIN OF EARTHQUAKES?

2009 ◽  
Vol 23 (28n29) ◽  
pp. 5374-5382 ◽  
Author(s):  
MASSIMO PICA CIAMARRA ◽  
LUCILLA DE ARCANGELIS ◽  
EUGENIO LIPPIELLO ◽  
CATALDO GODANO
Keyword(s):  
Confining Pressure ◽  
Stick Slip ◽  
Slip Regime ◽  
Constant Rate ◽  
Large Fluctuations ◽  
System Flow ◽  
System Phase Diagram ◽  
Dynamics Simulations ◽  
Stick Slip Motion ◽  
System Phase

Via Molecular Dynamics simulations, we investigate the stick-slip motion in a model of fault, where two surfaces subject to a constant confining pressure P, and enclosing granular particles, are subject a shear stress σ. When the system sticks, the stress increases with a constant rate [Formula: see text], while the stress decreases when the system flow. We dermine the system 'phase diagram' in the pressure P load velocity [Formula: see text] plane, locating the transition form the continuos flow regime to the stick-slip regimes, and show that the transition between these two regimes is characterized by the presence of large fluctuations. In the stick-slip regime, the system reproduces the behaviour of a segment of a fault of fixed lenght.

Experimental Investigation of Power Umbilical Damping

2017 ◽  
Author(s):  
Torfinn Ottesen
Keyword(s):  
Steady State ◽  
Energy Input ◽  
State Energy ◽  
Seawater Temperature ◽  
Structural Damping ◽  
Stick Slip ◽  
Slip Regime ◽  
Free Decay ◽  
Vortex Induced Vibrations ◽  
Slip Transition

Ocean currents may cause vortex induced vibrations (VIV) of deep-water umbilicals and cables. Since the VIV response may give significant contributions to the total fatigue damage it is important to know the structural damping for relevant curvature levels. A laboratory test has been performed on a 12.5 m long test specimen to determine the damping for a range of curvature levels that are in the vicinity of the stick-slip transition region. The energy input to maintain steady state oscillations with curvature amplitudes in the range 0.0002–0.001 m−1 was measured. The steady state energy input is consistent with damping ratios obtained using the free decay method. The structural damping depends on construction temperature and curvature and is less for typically low seawater temperature and low curvatures. The transition between the stick- and the slip regime is seen for typical seawater temperature.

Characteristics evaluation of gas film in the aerostatic thrust bearing within rarefied effect

2016 ◽  
Vol 231 (2) ◽  
pp. 149-157 ◽  
Author(s):  
Dongju Chen ◽  
Shuai Zhou ◽  
Jihong Han ◽  
Jinwei Fan ◽  
Qiang Cheng
Keyword(s):  
Machine Tool ◽  
Reynolds Equation ◽  
Thrust Bearing ◽  
Film Flow ◽  
Machining Accuracy ◽  
Aerostatic Bearing ◽  
Supply Pressure ◽  
Slip Regime ◽  
Key Factor ◽  
Gas Supply

The characteristic of gas film is a key factor in the performance of the aerostatic bearing. Because the gas film flow is in the slip regime, influence of the rarefied effect is significant. The modified Reynolds equation suitable for compressible gas in the rarefied effect is deduced through introducing the flow factor in the rarefied effect to the Reynolds equation. Pressure distribution, capacity, and stiffness of the gas film under the rarefied effect are analyzed. With the increase of gas pressure, the gas film capacity and stiffness of bearing would also increase. However, the greater the gas supply pressure, the more intense the gas film vibration, so it was important to select a reasonable gas supply pressure for achieving the optimal gas film characteristic. Finally, the gas rarefied effect is verified by the experiment indirectly, which agreed well with the analytical results and provided a theoretical guidance for the machining accuracy of the machine tool.

scholarly journals Numerical modeling of time-dependent bio-convective stagnation flow of a nanofluid in slip regime

2017 ◽  
Vol 7 ◽  
pp. 3325-3332 ◽  
Author(s):  
Rakesh Kumar ◽  
Shilpa Sood ◽  
Sabir Ali Shehzad ◽  
Mohsen Sheikholeslami
Keyword(s):  
Numerical Modeling ◽  
Time Dependent ◽  
Stagnation Flow ◽  
Slip Regime

Computing Micro Synthetic Jet in Slip Regime With Moving Membrane

2002 ◽  
Author(s):  
A. Rustem Aslan ◽  
Oktay Baysal ◽  
Firat O. Edis
Keyword(s):  
Moving Boundary ◽  
Pressure Field ◽  
Wall Slip ◽  
Synthetic Jet ◽  
Navier Stokes ◽  
Rarefied Flows ◽  
Flow Simulations ◽  
Slip Regime ◽  
Velocity Magnitude ◽  
Primary Focus

A Navier-Stokes (NS) solver for moving and deforming meshes has been modified to investigate numerically the diaphragm-driven flow in and out of two synthetic jet cavity geometries. The piezoelectric-driven diaphragm of the cavity is modeled in a realistic manner as a moving boundary to accurately compute the flow inside the jet cavity. The primary focus of the present paper is to describe the effect of cavity geometry and the wall slip, resulting from the relatively larger Kn number flows associated with micro sized geometries, on the exit jet velocity magnitude. Compressible flow simulations are required for rarefied flows to accurately predict the pressure field. The present computations for the quiescent external flow condition reveal that cavity geometry and the wall slip has an increasing effect on the magnitude of the average jet exit velocity as well as vortex shedding from the orifice.

CFD Study on the Flow Characteristics in Filleted Microchannels

2011 ◽  
Vol 103 ◽  
pp. 268-273
Author(s):  
Hong Jie Yan ◽  
Ping Zhou ◽  
Ze Lin Xu ◽  
Zhuo Chen ◽  
Jing Wen Mo
Keyword(s):  
Pressure Drop ◽  
Aspect Ratio ◽  
Flow Model ◽  
Constant Width ◽  
Flow Characteristics ◽  
Flow Pressure ◽  
Cfd Method ◽  
Poiseuille Number ◽  
The Relationship ◽  
Laminar Flow Model

The flow characteristics of water in filleted microchannels were simulated based on CFD method. The flow pressure drop at different aspect ratioandRenumber were rearranged on the simulating results with laminar flow model. The results indicated that the pressure drop enlarges with the increase of in the case of the constant width of the microchannel. Within the range ofRenumber of interest, Poiseuille number of the flow is constant for differentRe, but decreases with increasing aspect ratio. An equation was fitted to describe the relationship betweenPonumber and aspect ratio, i.e. .

scholarly journals An improved particle population balance equation in the continuum-slip regime

2016 ◽  
Vol 20 (3) ◽  
pp. 921-926 ◽  
Author(s):  
Mingliang Xie ◽  
Jin Li ◽  
Tingting Kong ◽  
Qing He
Keyword(s):  
Asymptotic Behavior ◽  
Correction Factor ◽  
Balance Equation ◽  
Present Model ◽  
Population Balance ◽  
Population Balance Equation ◽  
Brownian Coagulation ◽  
Slip Regime ◽  
Particle Population ◽  
The Continuum

An improved moment model is proposed to solve the population balance equation for Brownian coagulation in the continuum-slip regime, and it reduces to a known one in open literature when the non-linear terms in the slip correction factor are ignored. The present model shows same asymptotic behavior as that in the continuum regime.

Fully-Developed Laminar Flow in Sinusoidal Grooves

2001 ◽  
Vol 123 (3) ◽  
pp. 656-661 ◽  
Author(s):  
Scott K. Thomas ◽  
Richard C. Lykins ◽  
Kirk L. Yerkes
Keyword(s):  
Contact Angle ◽  
Shear Stress ◽  
Volumetric Flow Rate ◽  
Numerical Data ◽  
Mean Velocity ◽  
Constant Property ◽  
Fully Developed Flow ◽  
Vapor Interface ◽  
The Mean ◽  
Poiseuille Number

The flow of a constant property fluid through a sinusoidal groove has been analyzed. A numerical solution of the conservation of mass and momentum equations for fully developed flow is presented. The mean velocity, volumetric flow rate, and Poiseuille number are presented as functions of the groove geometry, meniscus contact angle, and shear stress at the liquid-vapor interface. In addition, a semi-analytical solution for the normalized mean velocity in terms of the normalized shear stress at the meniscus is shown to agree with the numerical data quite well.

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