Hi all,

Does any one know that if there is a good book or papers on the CFD and acoustics. In particular, I am interested in the effect of acoustic energy dissipation on the fluid flow.

David

Aerodynamic acoustics

Thanks,

There is an acoustics source (say a horn) in my simulation problem. I want to include this term.

I will use a turbulence model (something like k-e model) in the simulation. Thus I have to study the energy generation due to acoustic energy and energy dissipation due to viscous force of fluid.

Can you suggest me a good book of that topic. I am thinking that the simulation of noise generated from fluid may be more mature, how is the reserse problem?

Thank you

David

Hi David,

the damping of acoustic waves in fluids is a function of frequency and generally very small for low frequencies. You can get some hints on this topic by looking for the damping of sound waves in the atmosphere.

Regards, Markus

Dear Sir

Is it necessary for accoustics we use the LES????

best regards SAM

The usage of LES for acoustic problems need some thought.It is possible that the small scales can contain a large amount of acoustic energy and the filtering might become an issue.Recent developments have focussed on subgrid scale acoustic models.

-H

Hi,

I think that lighthill's wave equation may be used to describe the damping of sound wave. What is the effect of damping of wave on the turbulence energy generation of the fluid and energy dissipation?

Do you have any suggestion?

Thanks,

David

There is usually not much energy in acoustic waves at low Mach numbers and so acoustic waves usually have little affect on fluid motion. There are exceptions where a largely coherent fluid instability can interact with an acoustic wave. For example lecture theatres often have resonant slots/holes designed to extract energy from impinging acoustic waves around the resonant frequency of the cavity. The energy from the wave drives the fluid motion in and out of the cavity which creates strong velocity gradients dissipating energy via the action of viscosity. Note that this works because the fluid instability is largely coherent unlike, say, turbulence. The acoustic wave only gives the fluid wave a weak nudge but the nudge is essentially the same each cycle allowing the local fluid motion to build up.