FW-H Method -Lighthill's Analogy

FW-H Method -Lighthill's Analogy

- The FW-H model generates the pressure acoustic signals (sound pressure).

ANSYS Wave Equation Model

23.3. Using the Acoustics Wave Equation Model

https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v195/flu_ug/section_yvq_cpc_hfb.html?q=wave%20equation%20in%20fluent

One important limitation of ANSYS Fluent’s FW-H model is that it is applicable only to predicting the propagation of sound toward free space. Therefore, while the model can be legitimately used to predict far-field noise due to external aerodynamic flows, such as the flows around ground vehicles and aircraft, it cannot be used for predicting the noise propagation inside ducts or wall-enclosed space.

paper on using FW-H for water through a pressure reducing valve

https://iopscience.iop.org/article/10.1088/1755-1315/49/6/062022/pdf

- paper on hydro-vibro acoustics with FSI of blood flow and the arterial wall

https://arxiv.org/ftp/arxiv/papers/1804/1804.03260.pdf

https://www.youtube.com/watch?v=gt-R5nfu4rQ

- for electric car noise generated by internal combustion engine is not an issue however other existing sources will be "heard" by the driver and passenger

- acoustic wave model used when observer in near-field 

- for jet noise when the observer is in the far-field and you have non negligible volume sources use the permeable FW-H model

- impermeable FW-H used for fan noise or propeller noise

- sound sources on the boundary evaluated

- Does not take volume sources into account

FW-H is an integral method that evaluates sound sources on control surface (i.e outer walls that transfer to FEA acoustic mesh boundary)

https://www.youtube.com/watch?v=FC5eCepIV1s

http://www.bu.edu/ufmal/files/2011/08/tutorial.pdf?TB_iframe=true