Acoustic Streaming in a Microchannel Cross Section
Recent advances in the fabrication of microfluidic systems require handling of live cells and other micro particles as well as mixing. All this can, for example, be achieved using acoustic radiation forces and the viscous drag from the streaming flow. Streaming: Due to the nonlinear terms in the Navier-Stokes equations, harmonic perturbation of the flow will lead to a net time-averaged flow ...
Piezoelectric Tonpilz Transducer
The tonpilz (sound mushroom) piezoelectric transducer is a transducer for relatively low frequency, high power sound emission. The transducer consists of piezoceramic rings stacked between massive ends and pre-stressed by a central bolt. The tail and head mass lower the resonance frequency of the device. In this model the frequency response of the transducer when the bolt is not pre-stressed ...
Loudspeaker Driver in a Vented Enclosure
This model of a boxed loudspeaker lets you apply a nominal driving voltage and extract the resulting sound pressure level in the outside room as a function of the frequency. The sensitivity, both on-axis and spatial, is determined as function of frequency. These are some of the most important design parameters for a loudspeaker. The electromagnetic properties of the driver are supplied from the ...
Acoustic-Structure Interaction with a Perfectly Matched Layer (PML)
This small tutorial model shows how to set up a model with a solid mechanics and a pressure acoustics domain including a common perfectly matched layer (PML). The PML is used to model an open or infinite domain for both the elastic waves and the pressure waves. Two configurations of PMLs exist (this model describes the first case which is also the most difficult to handle): 1. One PML should ...
Helmholtz Resonator with Flow: Interaction of Flow and Acoustics
Helmholtz resonators are used in exhaust systems, as they can attenuate a specific narrow frequency band. The presence of a flow in the system alters the acoustic properties of the resonator and the transmission loss of the subsystem. In this tutorial model, a Helmholtz resonator is located as a side branch to a main duct. The transmission loss through the main duct is investigated when a flow ...
Ultrasonic Flow Meter with Piezoelectric Transducers: Coupling between FEM and DG
Ultrasonic flow meters determine the velocity of a fluid flowing through a pipe by sending an ultrasonic signal across the flow at a skew angle. When there is no flow, the transmitting time between the transmitter and the receiver is the same for the signals sent in the upstream and downstream directions. Otherwise, the wave traveling downstream moves faster than the one traveling upstream, ...
Vibroacoustic Loudspeaker Simulation: Multiphysics with BEM-FEM
This model shows a full vibroacoustic analysis of a loudspeaker including driver, cabinet, and stand. It lets you apply a nominal driving voltage and extract the resulting sound pressure level in the cabinet and in the outside room, as well as the deformation of the cabinet and driver, for a given frequency. The loudspeaker stand is placed on a hard floor some distance from a wall, which is ...
Hollow Cylinder
Fluid acoustics coupled to structural objects, such as membranes or plates, represents an important application area in many engineering fields. Some examples are: * Loudspeakers * Acoustic sensors * Nondestructive impedance testing * Medical ultrasound diagnostics This model provides a general demonstration of an acoustic fluid phenomenon in 3D coupled to a solid object. In this study, the ...
Helmholtz Resonator Analyzed with Different Frequency Domain Solvers
This model simulates a simple three-dimensional axisymmetric Helmholtz resonator, a classic acoustics model of a resonating circuit with a known theoretical solution. The idealized version considered here consists of a tube and a closed volume in series which are exposed to a pulsatile pressure. Real-world phenomena explained by the resonator include amongst others the resonance from blowing ...
Anechoic Coating
Anechoic coatings are used for lowering visibility to sonars, for example on submarines. This model calculates the reflection, absorption, and transmission properties of an anechoic coating on a steel plate based on a setup from literature.