Simulation-Based Analysis of 3D Flow Inside a Micropump With Passive Valves

2007 ◽  
Author(s):  
A. F. Tabak ◽  
A. Solak ◽  
E. Y. Erdem ◽  
C. Akcan ◽  
S. Yesilyurt
Keyword(s):  
Flow Rate ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Driving Frequency ◽  
Arbitrary Lagrangian Eulerian ◽  
Navier Stokes Equations ◽  
New Developments ◽  
Arbitrary Lagrangian Eulerian Method ◽  
Simulation Based

It is expected that chemical, biological and environmental applications of microdevices will increase with new developments in micromachining techniques. In this work, a micropump design that utilizes passive valves and an actuated diaphragm is presented. The flow rate is controlled by the deflection and the frequency of the diaphragm’s displacement. Passive valves are used for directing the flow. Poiseuille flow analogy is used to generate the equivalent pressure drop and flow rate via modifying the viscosity in the valve-channel in order to replace the variation of the channel width due to valve movement. Overall flow in the micropump is governed by three-dimensional time-dependent Navier Stokes equations. Deformation of the domain due to moving boundaries that coincide with the diaphragm motion is handled with the arbitrary Lagrangian-Eulerian method. Flow rate, hydraulic power and the efficiency of the micropump are obtained with respect to driving frequency and displacement of the diaphragm.

Simulation-Based Analysis of a Biologically-Inspired Micropump With a Rotating Spiral Inside a Microchannel

2008 ◽  
Author(s):  
Mustafa Koz ◽  
Serhat Yesilyurt
Keyword(s):  
Numerical Solutions ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Arbitrary Lagrangian Eulerian ◽  
Asymptotic Results ◽  
Navier Stokes Equations ◽  
Rate Maximum ◽  
Finite Element Package ◽  
Resistive Force Theory

Microorganisms such as bacteria use their rotating helical flagella for propulsion speeds up to tens of tail lengths per second. The mechanism can be utilized for controlled pumping of liquids in microchannels. In this study, we aim to analyze the effects of control parameters such as axial span between helical rounds (wavelength), angular velocity of rotations (frequency), and the radius of the helix (amplitude) on the maximum time-averaged flow rate, maximum head, rate of energy transfer, and efficiency of the micropump. The analysis is based on simulations obtained from the three-dimensional time-dependent numerical model of the flow induced by the rotating spiral inside a rectangular-prism channel. The flow is governed by Navier-Stokes equations subject to continuity in time-varying domain due to moving boundaries of the spiral. Numerical solutions are obtained using a commercial finite-element package which uses arbitrary Lagrangian-Eulerian method for mesh deformations. Results are compared with asymptotic results obtained from the resistive-force-theory available in the literature.

Simulation-Based Analysis of the Micropropulsion With Rotating Corkscrew Motion of Flagella

2009 ◽  
Author(s):  
Mustafa Koz ◽  
Serhat Yesilyurt
Keyword(s):  
Cylindrical Channel ◽  
Stokes Equations ◽  
Center Of Mass ◽  
Three Dimensional ◽  
Equation Of Motion ◽  
Navier Stokes ◽  
Mesh Deformation ◽  
Navier Stokes Equations ◽  
Simulation Based ◽  
Commercial Package

Microorganisms such as ecoli bacterium can propel themselves by means of a corkscrew motion in flow regimes where the Reynolds number is much smaller than one and inertial propulsion methods are ineffective. Micropropulsion with the rotating corkscrew motion of flagella can prove useful as a navigation mechanism for microswimming robots in medical applications. In this work, we present the motion of a microswimmer that consists of an ellipsoid of length two-microns and diameter one micron with a flagellum of length two microns and diameter of 40 nanometers. The microswimmer resembles to a typical ecoli bacterium. We present the effect of parameters such as angular velocity and amplitude of the corkscrew motion. In simulations, time-dependent three-dimensional Navier-Stokes equations are solved in deforming mesh using a commercial package COMSOL. Mesh deformation is specified based on the displacement and rotation of the microswimmer that springs from the net force and torque around the center of mass due to the rotation of the corkscrew-like flagellum. The net linear and angular accelerations of the microswimmer are calculated using ordinary-differential equations that represent the equation of motion, and coupled with the Navier-Stokes equations and the mesh deformation. For simplicity, microswimmer is placed in a cylindrical channel of diameter 20 microns and length 60 microns.

Simulation for Wind Pressure of Pedestrian Bridge Induced by Main Line Train

2013 ◽  
Vol 423-426 ◽  
pp. 1268-1271 ◽  
Author(s):  
Li Jiang ◽  
Jia Liu ◽  
Shu Jin Li ◽  
Bai Feng Ji ◽  
You Fu Du
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Wind Pressure ◽  
Main Line ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Pedestrian Bridge ◽  
Simulation Based ◽  
Time Histories ◽  
Variation Process

Wind pressure of pedestrian bridge induced by main line train has been investigated using numerical simulation. Based on time-filtered Reynolds Averaged Navier-Stokes equations, meanwhile, the RNG k-ε turbulent model is selected to close the equations, the three-dimensional incompressible unsteady flow computational fluid dynamics model have been established by commercial software FLUENT. The distribution of wind pressure and the time histories of wind pressure on surface of the bottom of bridge are obtained, moreover, the characteristics of variation process are summarized.

Three Dimensional FSI Modelling of Sulcus Vocalis Disorders of Vocal Folds

2018 ◽  
Vol 34 (6) ◽  
pp. 791-800 ◽  
Author(s):  
A. Vazifehdoostsaleh ◽  
N. Fatouraee ◽  
M. Navidbakhsh ◽  
F. Izadi
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Vocal Folds ◽  
Element Model ◽  
Navier Stokes ◽  
Arbitrary Lagrangian Eulerian ◽  
Navier Stokes Equations ◽  
Flow Parameters ◽  
Sulcus Vocalis ◽  
Underlying Mechanisms

AbstractThe effect of sulcus vocalis on vocal folds function is investigated. A type II sulcus vocalis is defined, parameterized and incorporated into a three-dimensional, fully coupled finite element model of vocal folds and laryngeal airway. The proposed Fluid-Structure Interaction (FSI) model is utilized in computational fluid dynamics, Arbitrary Lagrangian-Eulerian (ALE), incompressible continuity and Navier-Stokes equations and in a structure range of a three-layer elastic linear model. Flow parameters, vibration behavior and glottal jet aerodynamics of healthy and patient vocal folds models are compared with each other. Flow visualization is utilized to characterize Coanda effect and three dimensionality of flow patterns. The vibration frequency of vocal folds having sulcus vocalis decreases in comparison with that of healthy ones. Upon increasing the volume flux in the sulcus vocalis model, the non-periodic and disordered behavior of it is visible for patient vocal folds. Underlying mechanisms for the observed changes, possible implications for treatments of sulcus vocalis and human perfect voice production are also discussed.

scholarly journals THREE-DIMENSIONAL BIOMECHANICAL AND VISUALISATION MODEL OF VERTIGO DISEASE IN THE SEMI-CIRCULAR CANAL

2016 ◽  
Vol 7 (2) ◽  
Author(s):  
Žarko Milošević ◽  
Dalibor Nikolić ◽  
Igor Saveljić ◽  
Velibor Isailović ◽  
Thanos Bibas ◽  
...  
Keyword(s):  
Stokes Equations ◽  
Numerical Models ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Patient Specific ◽  
Arbitrary Lagrangian Eulerian ◽  
Navier Stokes Equations ◽  
Specific Patient ◽  
Continuity Equations ◽  
Ale Formulation

Benign paroxysmal positional vertigo (BPPV) is the most common type of vertigo. The symptoms of BPPV typically appear after angular movements of the head. BPPV leads to dizziness, nausea and imbalance. In this study, we examined a model of the semi-circular canal (SCC) with fully 3D three dimensional anatomical data from specific patient. A full Navier-Stokes equations and continuity equations are used for fluid domain with Arbitrary-Lagrangian Eulerian (ALE) formulation for mesh motion of finite element. Fluid-structure interaction for fluid coupling with cupula deformation is used. Particle tracking algorithm is implemented for particle motion. Motion of the otoconia particles which is main cause for BPPV is simulated. Velocity distribution, shear stress and force from endolymph side are presented for patient specific three SCC. We compared our numerical models with experiments with head moving and nystagmus eye tracking. Numerical simulation can give more details and understanding of the pathology of the specific patient in standard clinical diagnostic and therapy procedure for BPPV.

scholarly journals NUMERICAL SOLUTION OF FLUID-STRUCTURE INTERACTION PROBLEMS WITH CONSIDERING OF CONTACTS

2021 ◽  
Vol 61 (SI) ◽  
pp. 155-162
Author(s):  
Petr Sváček
Keyword(s):  
Stokes Equations ◽  
Fluid Motion ◽  
Reynolds Numbers ◽  
Navier Stokes ◽  
Computational Domain ◽  
Arbitrary Lagrangian Eulerian ◽  
Navier Stokes Equations ◽  
Computational Mesh ◽  
Arbitrary Lagrangian Eulerian Method ◽  
High Reynolds

This paper is interested in the mathematical modelling of the voice production process. The main attention is on the possible closure of the glottis, which is included in the model with the concept of a fictitious porous media and using the Hertz impact force The time dependent computational domain is treated with the aid of the Arbitrary Lagrangian-Eulerian method and the fluid motion is described by the incompressible Navier-Stokes equations coupled to structural dynamics. In order to overcome the instability caused by the dominating convection due to high Reynolds numbers, stabilization procedures are applied and numerically analyzed for a simplified problem. The possible distortion of the computational mesh is considered. Numerical results are shown.

Effects of stator splitter blades on aerodynamic performance of a single-stage transonic axial compressor

2020 ◽  
Vol 14 (4) ◽  
pp. 7369-7378
Author(s):  
Ky-Quang Pham ◽  
Xuan-Truong Le ◽  
Cong-Truong Dinh
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Aerodynamic Performance ◽  
Numerical Results ◽  
Single Stage ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Operating Stability ◽  
Length Coverage

Splitter blades located between stator blades in a single-stage axial compressor were proposed and investigated in this work to find their effects on aerodynamic performance and operating stability. Aerodynamic performance of the compressor was evaluated using three-dimensional Reynolds-averaged Navier-Stokes equations using the k-e turbulence model with a scalable wall function. The numerical results for the typical performance parameters without stator splitter blades were validated in comparison with experimental data. The numerical results of a parametric study using four geometric parameters (chord length, coverage angle, height and position) of the stator splitter blades showed that the operational stability of the single-stage axial compressor enhances remarkably using the stator splitter blades. The splitters were effective in suppressing flow separation in the stator domain of the compressor at near-stall condition which affects considerably the aerodynamic performance of the compressor.

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