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Help with Definition Error: Surface Integration of Acoustic Pressure on Solid Boundaries

Posted Jun 1, 2026, 5:38 p.m. EDT Acoustics & Vibrations Version 6.0 0 Replies

Azaria Tsegaye

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Hi everyone, I am running a room acoustics simulation using the Pressure Acoustics, Frequency Domain (acpr) interface. My model consists of a standard air domain with a solid concrete inertia block located inside the room. I need to calculate the total acoustic pressure acting on the block. I am doing this via Surface Integration of the total acoustic pressure (acpr.p_t) over the shared boundaries between the air domain and the solid block. However, COMSOL keeps an error, stating that the acoustic pressure variable is not defined on these boundaries. I know this happens because acoustics don’t exist within solid domains , but I still need to find a way to compute this surface integral at those eganfrequienceis. As a test, I tried converting the solid block's material properties to air. While that fixes the error, it completely alters the acoustic cavity volume and gives me wildly different acoustic modes/frequencies, so that workaround won't work for my setup. Does anyone know a way to evaluate a fluid variable like acoustic pressure right at the interface of an inactive solid domain? Would creating a very thin "shelled" air domain wrapper around the solid plinth be a viable workaround, or is there a better built-in way to only look at the fluid side of the boundary during integration? Please look at the results secion titled eganfrequecny study because that is where my egenfrequecies are from Best, Azaria

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comsolsurfacearearoomacusticspostsmalll3.mph

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