COMSOL - Plane Wave Radiation input not matching Pressure Field

In summary, the conversation discusses a model set up with a cuboid and a membrane, similar to an impedance tube setup. Integration and Explicit tools were used to define an 'inlet' and 'outlet' at opposing faces with Variables intop1(p0) and intop2(p). Plane Wave Radiation was then added to the model with an Incident Pressure Field at the inlet and a Pressure Amplitude set to p0 = 20 Pa. However, the resulting Acoustic Pressure at the 1st Eigenfrequency showed an incorrect scale, with the pressure at the inlet only at 1x10^-11 Pa. The speaker is seeking clarification on this discrepancy.
  • #1
pitchtwit
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I have a model set up, that is a cuboid, with a membrane half-way along - a bit like an impedance tube setup.

I've used Integration 1 & 2 with Explicit 1 & 2 to define an 'inlet' and 'outlet' at opposing faces of the tube. The Variables for the inlet and outlet are intop1(p0) and intop2(p).

I then added Plane Wave Radiation to the model (inlet & outlet), with the Incident Pressure Field on just the inlet set with a Pressure Amplitude p0 = 20 Pa.

The resulting Acoustic Pressure at the 1st Eigenfrequency shows that the flow direction is correct, but the scale is odd. It shows that the pressure at the inlet is about 1x10^-11 Pa.

How can this be, when I set the inlet pressure to be 20 Pa?

Many thanks.

https://dl.dropboxusercontent.com/u/11341635/Screen%20Shot%202014-08-12%20at%2008.35.20.png
 
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  • #2
I'm sorry you are not finding help at the moment. Is there any additional information you can share with us?
 

1. What is COMSOL and how is it used in scientific research?

COMSOL is a powerful software tool used in scientific research for modeling and simulating physical phenomena. It uses numerical methods to solve mathematical equations and allows researchers to analyze and predict the behavior of complex systems.

2. What is the "Plane Wave Radiation input" in COMSOL and how does it relate to the Pressure Field?

The Plane Wave Radiation input in COMSOL refers to a type of boundary condition where a plane wave of electromagnetic or acoustic energy is incident on a surface. This input is used to simulate the effect of external sources on the system being modeled. The Pressure Field, on the other hand, is the distribution of pressure throughout the system and is affected by the Plane Wave Radiation input through the boundary condition.

3. Why might the Plane Wave Radiation input not match the Pressure Field in COMSOL?

There could be several reasons for a mismatch between the Plane Wave Radiation input and the Pressure Field in COMSOL. One possibility is that the boundary conditions are not properly defined, leading to incorrect simulation results. Another reason could be that the chosen numerical methods or parameters are not suitable for the given system, resulting in discrepancies between the input and output.

4. How can I troubleshoot a mismatch between the Plane Wave Radiation input and the Pressure Field in COMSOL?

To troubleshoot this issue, you can start by reviewing the boundary conditions and making sure they are correctly defined. You can also try adjusting the numerical methods and parameters, such as the mesh size and solver settings, to see if it improves the match between the input and output. It may also be helpful to consult the COMSOL user manual or seek assistance from other researchers familiar with the software.

5. Is there a way to validate the accuracy of the Plane Wave Radiation input and Pressure Field in COMSOL?

Yes, there are several ways to validate the accuracy of the Plane Wave Radiation input and Pressure Field in COMSOL. One approach is to compare the simulation results with experimental data or analytical solutions, if available. Another way is to conduct convergence studies by varying the mesh size and checking if the results converge to a certain value. Additionally, you can also use sensitivity analysis to determine the impact of different input parameters on the output.

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