Related Experiment Video
Updated: Apr 29, 2026
08:32
Assembly and Characterization of an External Driver for the Generation of Sub-Kilohertz Oscillatory Flow in Microchannels
Published on: January 28, 2022
2.0K
Steady flows above a quartz crystal resonator driven at elevated amplitude
Rebekka König1, Arne Langhoff1, Diethelm Johannsmann1
1Institute of Physical Chemistry, Arnold-Sommerfeld-Strasse 4, D-38678 Clausthal-Zellerfeld, Germany.
Summary
Acoustically driven steady liquid flow was observed above quartz crystal microbalances. This novel flow, driven by nonlinear Navier-Stokes equations, has potential applications in sensing and microfluidics.
Area of Science:
- Physics
- Fluid Dynamics
- Acoustics
Background:
- Quartz crystal microbalances (QCMs) are widely used in sensing applications.
- Understanding fluid dynamics near oscillating surfaces is crucial for optimizing QCM performance.
- Nonlinear effects in fluid mechanics can lead to complex phenomena.
Purpose of the Study:
- To investigate the occurrence and characteristics of steady liquid flow above an oscillating QCM surface.
- To elucidate the underlying physical mechanisms driving this acoustically induced flow.
- To explore potential applications of this phenomenon in microfluidics and sensing.
Main Methods:
- Experimental observation of liquid flow above a QCM surface under specific oscillation conditions.
- Theoretical analysis utilizing the Navier-Stokes equation, including nonlinear terms.
- Characterization of flow patterns, velocity profiles, and dependence on oscillation amplitude.
Main Results:
- A steady streaming flow of liquid was observed above the QCM surface when oscillation amplitude exceeded 10 nm.
- The flow is parallel to the displacement vector and directed towards the plate's center.
- The flow is attributed to the nonlinear term in the Navier-Stokes equation and flexural admixtures in the resonator's vibration.
Conclusions:
- Acoustically driven steady flow presents a new mechanism in microfluidics and micromechanics.
- The flow's unique velocity profile, maximal at a distance from the surface, is effective for detaching adsorbed particles.
- The observed flow pattern serves as a diagnostic tool for analyzing resonator vibration modes, particularly flexural admixtures.
Related Concept Videos
01:28Standing Waves in a Cavity
1.7K
A household microwave and lasers are examples of standing electromagnetic waves in a cavity. When two conducting metal plates are placed parallel at the nodal planes, it creates a cavity where standing waves are formed. The cavity between the two planes is analogous to a stretched string held at the points x = 0 and x = L. Here, the distance 'L' between the two planes must be an integer multiple of half of the wavelength. The wavelengths that satisfy this condition are given by:
1.7K
01:06Forced Oscillations
6.3K
When an oscillator is forced with a periodic driving force, the motion may seem chaotic. The motions of such oscillators are known as transients. After the transients die out, the oscillator reaches a steady state, where the motion is periodic, and the displacement is determined.
6.3K
01:19Concept of Resonance and its Characteristics
5.4K
If a driven oscillator needs to resonate at a specific frequency, then very light damping is required. An example of light damping includes playing piano strings and many other musical instruments. Conversely, to achieve small-amplitude oscillations as in a car's suspension system, heavy damping is required. Heavy damping reduces the amplitude, but the tradeoff is that the system responds at more frequencies. Speed bumps and gravel roads prove that even a car's suspension system is not...
5.4K
01:30Oscillations In An LC Circuit
2.7K
An idealized LC circuit of zero resistance can oscillate without any source of emf by shifting the energy stored in the circuit between the electric and magnetic fields. In such an LC circuit, if the capacitor contains a charge q before the switch is closed, then all the energy of the circuit is initially stored in the electric field of the capacitor. This energy is given by
2.7K
01:14Sound Waves: Resonance
2.8K
Resonance is produced depending on the boundary conditions imposed on a wave. Resonance can be produced in a string under tension with symmetrical boundary conditions (i.e., has a node at each end). A node is defined as a fixed point where the string does not move. The symmetrical boundary conditions result in some frequencies resonating and producing standing waves, while other frequencies interfere destructively. Sound waves can resonate in a hollow tube, and the frequencies of the sound...
2.8K
01:17Standing Waves
4.3K
Sometimes waves do not seem to move; rather, they just vibrate in place. Unmoving waves can be seen on the surface of a glass of milk kept in a refrigerator, which is one example of standing waves. Vibrations from the refrigerator motor create waves on the milk that oscillate up and down but do not seem to move across the surface. These waves are formed or created by the superposition of two or more identical moving waves in opposite directions. The waves move through each other, with their...
4.3K