Two Dimensional Acoustic Manipulation in Microfluidic Channels

2011 ◽  
Vol 117-119 ◽  
pp. 624-632
Author(s):  
Lin Xu ◽  
Adrian Neild
Keyword(s):  
Standing Wave ◽  
Acoustic Radiation ◽  
Standing Waves ◽  
Microfluidic Channels ◽  
Two Dimensional ◽  
Positioning Control ◽  
One Dimensional ◽  
Pressure Fields ◽  
Radiation Forces ◽  
Solid Walls

Acoustic radiation forces can be used to collect particles within microfluidic systems. The standard way of doing this is to excite a one-dimensional standing wave between a pair of solid walls; the particles will then typically collect at the pressure nodes. Higher degrees of positioning control can be achieved by excitation of additional orthogonal one-dimensional standing waves; this usually requires further walled constraints (two-dimensional collection for example requiring a chamber rather than a channel). In this work we examine methods of exciting two-dimensional fields in a channel using a single transducer as well as the use of pressure fields which are not one-dimensional in nature and the advantages they can offer.

On the observability of finite-depth short-crested water waves

1996 ◽  
Vol 322 ◽  
pp. 1-19 ◽  
Author(s):  
M. Ioualalen ◽  
A. J. Roberts ◽  
C. Kharif
Keyword(s):  
Standing Wave ◽  
Water Waves ◽  
Numerical Study ◽  
Standing Waves ◽  
Finite Depth ◽  
Two Dimensional ◽  
Wave Fields ◽  
Progressive Waves ◽  
Wave Limit ◽  
Narrow Bands

A numerical study of the superharmonic instabilities of short-crested waves on water of finite depth is performed in order to measure their time scales. It is shown that these superharmonic instabilities can be significant-unlike the deep-water case-in parts of the parameter regime. New resonances associated with the standing wave limit are studied closely. These instabilities ‘contaminate’ most of the parameter space, excluding that near two-dimensional progressive waves; however, they are significant only near the standing wave limit. The main result is that very narrow bands of both short-crested waves ‘close’ to two-dimensional standing waves, and of well developed short-crested waves, perturbed by superharmonic instabilities, are unstable for depths shallower than approximately a non-dimensional depth d= 1; the study is performed down to depth d= 0.5 beyond which the computations do not converge sufficiently. As a corollary, the present study predicts that these very narrow sub-domains of short-crested wave fields will not be observable, although most of the short-crested wave fields will be.

scholarly journals Numerical Simulation of Boundary-Driven Acoustic Streaming in Microfluidic Channels with Circular Cross-Sections

Micromachines ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 240 ◽  
Author(s):  
Junjun Lei ◽  
Feng Cheng ◽  
Kemin Li
Keyword(s):  
Cross Sections ◽  
Acoustic Pressure ◽  
Outer Boundary ◽  
Acoustic Streaming ◽  
Microfluidic Channels ◽  
Two Dimensional ◽  
Resonant Frequencies ◽  
Pressure Fields ◽  
Rectangular Channels ◽  
Limiting Velocity

While acoustic streaming patterns in microfluidic channels with rectangular cross-sections have been widely shown in the literature, boundary-driven streaming fields in non-rectangular channels have not been well studied. In this paper, a two-dimensional numerical model was developed to simulate the boundary-driven streaming fields on cross-sections of cylindrical fluid channels. Firstly, the linear acoustic pressure fields at the resonant frequencies were solved from the Helmholtz equation. Subsequently, the outer boundary-driven streaming fields in the bulk of fluid were modelled while using Nyborg’s limiting velocity method, of which the limiting velocity equations were extended to be applicable for cylindrical surfaces in this work. In particular, acoustic streaming fields in the primary (1, 0) mode were presented. The results are expected to be valuable to the study of basic physical aspects of microparticle acoustophoresis in microfluidic channels with circular cross-sections and the design of acoustofluidic devices for micromanipulation.

scholarly journals Orbital Shaped Standing Waves Using Chladni Plates

2019 ◽  
Author(s):  
Eric Janusson ◽  
Johanne Penafiel ◽  
Andrew Macdonald ◽  
Shaun MacLean ◽  
Irina Paci ◽  
...  
Keyword(s):  
Standing Wave ◽  
Atomic Orbital ◽  
Three Dimensional ◽  
Standing Waves ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Cross Sectional ◽  
Atomic Orbitals ◽  
Chemistry Students

Chemistry students are often introduced to the concept of atomic orbitals with a representation of a one-dimensional standing wave. The classic example is the harmonic frequencies which produce standing waves on a guitar string; a concept which is easily replicated in class with a length of rope. From here, students are typically exposed to a more realistic three-dimensional model, which can often be difficult to visualize. Extrapolation from a two-dimensional model, such as the vibrational modes of a drumhead, can be used to convey the standing wave concept to students more easily. We have opted to use Chladni plates which may be tuned to give a two-dimensional standing wave which serves as a cross-sectional representation of atomic orbitals. The demonstration, intended for first year chemistry students, facilitates the examination of nodal and anti-nodal regions of a Chladni figure which students can then connect to the concept of quantum mechanical parameters and their relationship to atomic orbital shape.

scholarly journals Long waves over a bi-viscous seabed: transverse patterns

2002 ◽  
Vol 9 (1) ◽  
pp. 61-68
Author(s):  
J. M. Becker ◽  
D. Bercovici
Keyword(s):  
Yield Stress ◽  
Standing Wave ◽  
Lower Layer ◽  
Two Dimensional ◽  
One Dimensional ◽  
Wave Forcing ◽  
Model Response ◽  
Two Layer Model ◽  
Constant Yield ◽  
Simple Dynamical Model

Abstract. The coupled interaction of long standing hydrodynamic waves with a deformable non-Newtonian seabed is examined using a two-layer model for which the upper layer fluid is inviscid and the lower layer is bi-viscous. The two-dimensional response of the system to forcing by a predominantly longitudinal (cross-shore) standing wave perturbed by a small transverse (along-shore) component is determined. With a constant yield stress in the bi-viscous lower layer, there is little amplification of these transverse per-turbations and the model response typically remains quasi-one-dimensional. However, for a bi-viscous layer with a pressure-dependent yield stress (which represents the effect that the seabed deforms less readily under compression and hence renders the rheology history dependent), the initially small transverse motions are amplified in some parameter regimes and two-dimensional, permanent bedforms are formed in the lower layer. This simple dynamical model is, therefore, able to explain the formation of permanent bedforms with significant cross- and along-shore features by predominantly cross-shore standing wave forcing.

scholarly journals Relatioship of peaks of correlation functions of amplitude and phase fluctuations with eigen frequencies in oscillation spectrum

2015 ◽  
Vol 1 (3) ◽  
pp. 62-71
Author(s):  
Андрей Поляков ◽  
Andrey Polyakov
Keyword(s):  
Correlation Functions ◽  
Standing Waves ◽  
Cavity Resonator ◽  
Signal Amplitude ◽  
Signal Spectrum ◽  
Universal Relation ◽  
Two Dimensional ◽  
Phase Fluctuations ◽  
One Dimensional ◽  
The Difference

Method of correlation functions of signal amplitude and phase fluctuations (CFAP) is used for processing oscillations in one-dimensional and two-dimensional rectangular cavity resonator models. For all cases, a universal relation, which gives a relationship between the repetition period of peaks on CFAP functions and the difference of adjacent eigenfrequencies in the signal spectrum was obtained. It is shown that for two-dimensional standing wave, this difference can have only two values, each of which corresponds to eigenfrequencies of one-dimensional standing waves. The proposed method allows us to detect all possible one-dimensional standing waves which can occur in the object under study.

scholarly journals Manipulation of particles in two dimensions using phase controllable ultrasonic standing waves

2011 ◽  
Vol 468 (2138) ◽  
pp. 337-360 ◽  
Author(s):  
C. R. P. Courtney ◽  
C.-K. Ong ◽  
B. W. Drinkwater ◽  
A. L. Bernassau ◽  
P. D. Wilcox ◽  
...  
Keyword(s):  
Acoustic Radiation ◽  
Sudden Change ◽  
Standing Waves ◽  
Radiation Force ◽  
Two Dimensions ◽  
Two Dimensional ◽  
Dimensional Plane ◽  
System A ◽  
Propagating Waves ◽  
The Relationship

The ability to manipulate dense micrometre-scale objects in fluids is of interest to biosciences with a view to improving analysis techniques and enabling tissue engineering. A method of trapping micrometre-scale particles and manipulating them on a two-dimensional plane is proposed and demonstrated. Phase-controlled counter-propagating waves are used to generate ultrasonic standing waves with arbitrary nodal positions. The acoustic radiation force drives dense particles to pressure nodes. It is shown analytically that a series of point-like traps can be produced in a two-dimensional plane using two orthogonal pairs of counter-propagating waves. These traps can be manipulated by appropriate adjustment of the relative phases. Four 5 MHz transducers (designed to minimize reflection) are used as sources of counter-propagating waves in a water-filled cavity. Polystyrene beads of 10 μm diameter are trapped and manipulated. The relationship between trapped particle positions and the relative phases of the four transducers is measured and shown to agree with analytically derived expressions. The force available is measured by determining the response to a sudden change in field and found to be 30 pN, for a 30 V pp input, which is in agreement with the predictions of models of the system. A scalable fabrication approach to producing devices is demonstrated.

scholarly journals Orbital Shaped Standing Waves Using Chladni Plates

2019 ◽  
Author(s):  
Eric Janusson ◽  
Johanne Penafiel ◽  
Andrew Macdonald ◽  
Shaun MacLean ◽  
Irina Paci ◽  
...  
Keyword(s):  
Standing Wave ◽  
Atomic Orbital ◽  
Three Dimensional ◽  
Standing Waves ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Cross Sectional ◽  
Atomic Orbitals ◽  
Chemistry Students

Chemistry students are often introduced to the concept of atomic orbitals with a representation of a one-dimensional standing wave. The classic example is the harmonic frequencies which produce standing waves on a guitar string; a concept which is easily replicated in class with a length of rope. From here, students are typically exposed to a more realistic three-dimensional model, which can often be difficult to visualize. Extrapolation from a two-dimensional model, such as the vibrational modes of a drumhead, can be used to convey the standing wave concept to students more easily. We have opted to use Chladni plates which may be tuned to give a two-dimensional standing wave which serves as a cross-sectional representation of atomic orbitals. The demonstration, intended for first year chemistry students, facilitates the examination of nodal and anti-nodal regions of a Chladni figure which students can then connect to the concept of quantum mechanical parameters and their relationship to atomic orbital shape.

A one-dimensional self-gravitating stellar gas

1966 ◽  
Vol 25 ◽  
pp. 46-48 ◽  
Author(s):  
M. Lecar
Keyword(s):  
Gravitational Field ◽  
Phase Space ◽  
Motion Picture ◽  
Space Distribution ◽  
Two Dimensional ◽  
One Dimensional ◽  
Phase Space Distribution ◽  
Dimensional Phase Space ◽  
The Mean

“Dynamical mixing”, i.e. relaxation of a stellar phase space distribution through interaction with the mean gravitational field, is numerically investigated for a one-dimensional self-gravitating stellar gas. Qualitative results are presented in the form of a motion picture of the flow of phase points (representing homogeneous slabs of stars) in two-dimensional phase space.

Sign in / Sign up

Export Citation Format

Share Document