Generic Nacelle with an Acoustic Liner
Application ID: 141081
This model demonstrates two approaches to model the acoustics in a generic nacelle with an acoustic liner and a background flow. The first method uses the Compressible Potential Flow and the* Linearized Potential Flow, Frequency Domain* interfaces, while the second, more detailed approach, uses a turbulent background flow and the Linearized Navier–Stokes, Frequency Domain interface.
In the first approach, based on a linearized potential flow equations, the acoustic liner is modeled using the Brambley option for the impedance condition. This is an extended version of the Ingard–Myers boundary condition which takes into account the thickness of the turbulent boundary layer of the background flow field. A propagating acoustic mode with a radial and azimuthal wave number is actuated using a Port condition.
In the second approach, based on the linearized Navier–Stokes equations, the propagating modes are found with the Linearized Navier–Stokes, Boundary Mode interface and then used as a background field to excite the system with the correct acoustic mode. The results of the two approaches are compared.
This model example illustrates applications of this type that would nominally be built using the following products:
however, additional products may be required to completely define and model it. Furthermore, this example may also be defined and modeled using components from the following product combinations:
- COMSOL Multiphysics® and
- Acoustics Module and
- either the CFD Module, or Heat Transfer Module
The combination of COMSOL® products required to model your application depends on several factors and may include boundary conditions, material properties, physics interfaces, and part libraries. Particular functionality may be common to several products. To determine the right combination of products for your modeling needs, review the Tabella delle Funzionalità and make use of a free evaluation license. The COMSOL Sales and Support teams are available for answering any questions you may have regarding this.