# Air flow through a speaker box

I want to model the air flow through a speaker box. How do I set the physics to allow for a set of frequencies? Also, how do I model a box with a single Inlet/Outlet (tuning port) and a 'closed' source of air movement (speaker)?

I am an electronics guy so the world of CFD is all new to me. Thanks for your help and suggestions.

PS: I am using the 32-bit version.

Thanks,
Dave

### Standard RANS can not model acoustics

I don't believe that the assumptions by the standard Reynolds Averaged Navier Stokes (RANS) CFD approach in Caedium can help with sound wave simulation. The small pressure and velocity fluctuations will not be represented correctly.

### still hoping...

Given that the speed of sound is ~1200ft/s would it be able to simulate a constant air-flow instead of an oscillating air-flow? Ultimately I want to see what kind of turbulence a speaker box design will create. Then, if possible, I'd like to make small changes to the box design and see if that turbulence can be improved. Can you suggest anything that would allow me to do this?

I was able to create a box and set up the physics to have a closed end (speaker) and an opening set as Inlet/Outlet but the results returned an error. I will re-try using an inlet where the speaker goes and an outlet at the tuning port and see what results I get.

Thanks

### Not going to work

The standard RANS solver in Caedium can not simulate standing waves. There has to be at least one outlet for one or more inlets, and vice versa. There is a (complex) relationship between turbulent kinetic energy and sound generation, but there has to be a mean flow for a simulation to work.

The approach you are taking will provide no meaningful results.

### Is there a way?

Is there a solver other than RANS that would work?

Is it possible to set up an inlet to oscillate at a set frequency?

Can I set both 'ends' to inlet/outlets and have a particle seed at each end to show the air flow in small bursts from each end?

### No can do

You can't do this type of simulation in Caedium. If there was a way I would share it!