What is the difference between the scattering BC and PML?

Thread starter faryafada
Start date Mar 23, 2015
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Comsol Difference Scattering

In summary, the scattering boundary condition (BC) and perfectly matched layer (PML) are both techniques used in simulations to reduce reflections and simulate an infinite domain. However, they differ in their implementation, with scattering BCs adding additional terms to governing equations and PMLs using a complex coordinate transformation. While both aim to achieve similar results, PMLs are designed to completely absorb outgoing waves, while scattering BCs may produce some unwanted reflections. The choice between the two depends on the specific application and type of waves being simulated, with PMLs more commonly used in electromagnetic simulations and scattering BCs in acoustic and fluid dynamics simulations. However, both techniques have limitations, such as inaccuracies at certain angles or frequencies for scattering BCs and

Mar 23, 2015

faryafada

Hi,
I want to know what is the proper boundary condition in COMSOL RF module to study optical interactions, Scattering BC and PML? or what is the difference between them? also I want to know if the rules are different for application of these two BCs in far-field and near-fields studies?

Thanks,
Farya

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Mar 24, 2015

soarce

See here for instance http://www.comsol.com/community/forums/general/thread/12362/

What is the difference between the scattering BC and PML?

The scattering boundary condition (BC) is a type of boundary condition used in simulations to model scattering of waves at the edges of a domain. It is usually applied to the outermost boundaries of a computational domain and is used to simulate the effects of an infinite domain. On the other hand, the perfectly matched layer (PML) is a technique used to absorb outgoing waves in the computational domain, preventing them from reflecting back and causing interference. It is commonly used in electromagnetic simulations to mimic an open boundary condition.

How do scattering BC and PML differ in their implementation?

Scattering BCs are typically implemented by adding additional terms to the governing equations, while PMLs are usually implemented through the introduction of a complex coordinate transformation. This allows for a gradual attenuation of outgoing waves within the PML layer, effectively absorbing them without causing reflections.

Do scattering BC and PML produce similar results?

In terms of their overall purpose, both scattering BCs and PMLs aim to reduce reflections and simulate an infinite domain. However, their mechanisms of achieving this can lead to different results. Scattering BCs can produce some unwanted reflections, while PMLs are designed to completely absorb outgoing waves.

Which one is more commonly used in simulations?

The choice between scattering BCs and PMLs depends on the specific application and the type of waves being simulated. In general, PMLs are more commonly used in electromagnetic simulations, while scattering BCs are more commonly used in acoustic and fluid dynamics simulations.

What are the limitations of scattering BC and PML?

Scattering BCs may not be effective in absorbing waves at certain angles or frequencies, leading to inaccurate results. PMLs can also have limitations, such as the need for fine-tuning of parameters and increased computational cost. Additionally, both techniques may not be suitable for certain types of waves, such as surface waves or evanescent waves.